Post by: jamonwindeyer on October 21, 2016, 04:23:16 pm
Multiple Choice (JUST CLICK THE SPOILER BELOW)
Spoiler
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Section Two (JUST CLICK THE SPOILER BELOW)
Spoiler
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Markers Commentary
Spoiler
- The formula sheet stapled to the back is still a weird feeling.
- Multiple choice was VERY kind. No curveballs here. Students may have been confused about how to attempt the absolute value integral in Question 9, but besides that, pretty stock standard.
- Typical Question 11; nothing surprising here. No difficult questions, good warm up for the paper.
- Typical Question 12; geometry makes the return again. A fairly simple geometric proof for Part B; and a very generous amount of marks devoted to the cosine rule in Part C. Pretty stock standard.
- Very nice curve sketching question to start Question 13; it's nice to change from the typical cubic polynomial we get here. Strong students shouldn't have had too much trouble with the first three, very standard question types and processes. Part D could throw you just by the look of it, but really, it's just area between curves. Remember units squared!
- They were always going to put Simpson's Rule in this year; because they gave you an application that required either two uses of formula, or some clever symmetry work (or the full version of the formula). Not too difficult otherwise. The way they wrote the series in Part (b)(i) may have made it difficult to get (b)(ii), expanding it first helps. Part C is typical calculus, nothing algebraically difficult, but students may have been silly like me and not substituted your value back into the length formula ;) Part D and E were clever series manipulation questions; clear direction made D reasonably easy. Part E would have been hard if you didn't spot the trick and remember your Log Laws.
- 15(a) was our difficulty spike. It required clever consideration of how you'd take the Volume; by considering only part of each curve. A solid 4 marker; the integral itself behaves nicely. We get another series probability Question in Part B; BOSTES love these now (MX1 students have gotten them frequently for a few years); but it not being infinity was a nice change. A TOUGH geometry proof for Part C, but assigning pro numerals makes things much easier. The final sub-part is easier than what precedes it.
- A very generous start to Question 16 this time; motion questions are free marks if you interpret them correctly. Mostly basic calculus work, taking your graph in Part (iii) and applying it to (iv) was the conceptual challenge here.
- Final Question: Very kind, or at least, could be loads worse. Quotient rule for 2 marks; justifying the range may have been difficult if you aren't good at conceptualising/formalising limits. The rearrangement section may have proved to stump a few; but we can do Part (iv) regardless, and its only worth a mark. The wording of the last sub-part was clear but easily misinterpreted if time was running out (I made this mistake initially as well). Students who did more than about 6-7 lines of working for the last sub-part probably differentiated the result from part (i), which was gross. This idea of 'recursive derivative formulae' is actually really cool; I'd like to see it pop up more in the exams; leads well into uni.
Overall, this was not a tough 2U paper. Some very abstract questions; less of your common setups and more tricky things that require thinking on your feet. But no super disgusting questions like we had in the early 2000's, which is what I thought we'd be up against (I'm glad I was wrong). Series seems to be the weird one this year; they took it out of the MC completely and scattered it throughout. Interesting. 22 marks for Applications of Calculus to Physical World, so that remains a huge part of the exam (this is bigger than any year in recent memory, actually).
Overall, Band cut-offs should sit steady from last year, perhaps drop ever so slightly. I did the Exam in 1.5 hours and so far, based on corrections, I got ~93% raw. This puts it roughly in line with the more recent exams. I'd personally say it was easier than 2014, but perhaps harder than 2015 :)
What do you think? ;D
- Multiple choice was VERY kind. No curveballs here. Students may have been confused about how to attempt the absolute value integral in Question 9, but besides that, pretty stock standard.
- Typical Question 11; nothing surprising here. No difficult questions, good warm up for the paper.
- Typical Question 12; geometry makes the return again. A fairly simple geometric proof for Part B; and a very generous amount of marks devoted to the cosine rule in Part C. Pretty stock standard.
- Very nice curve sketching question to start Question 13; it's nice to change from the typical cubic polynomial we get here. Strong students shouldn't have had too much trouble with the first three, very standard question types and processes. Part D could throw you just by the look of it, but really, it's just area between curves. Remember units squared!
- They were always going to put Simpson's Rule in this year; because they gave you an application that required either two uses of formula, or some clever symmetry work (or the full version of the formula). Not too difficult otherwise. The way they wrote the series in Part (b)(i) may have made it difficult to get (b)(ii), expanding it first helps. Part C is typical calculus, nothing algebraically difficult, but students may have been silly like me and not substituted your value back into the length formula ;) Part D and E were clever series manipulation questions; clear direction made D reasonably easy. Part E would have been hard if you didn't spot the trick and remember your Log Laws.
- 15(a) was our difficulty spike. It required clever consideration of how you'd take the Volume; by considering only part of each curve. A solid 4 marker; the integral itself behaves nicely. We get another series probability Question in Part B; BOSTES love these now (MX1 students have gotten them frequently for a few years); but it not being infinity was a nice change. A TOUGH geometry proof for Part C, but assigning pro numerals makes things much easier. The final sub-part is easier than what precedes it.
- A very generous start to Question 16 this time; motion questions are free marks if you interpret them correctly. Mostly basic calculus work, taking your graph in Part (iii) and applying it to (iv) was the conceptual challenge here.
- Final Question: Very kind, or at least, could be loads worse. Quotient rule for 2 marks; justifying the range may have been difficult if you aren't good at conceptualising/formalising limits. The rearrangement section may have proved to stump a few; but we can do Part (iv) regardless, and its only worth a mark. The wording of the last sub-part was clear but easily misinterpreted if time was running out (I made this mistake initially as well). Students who did more than about 6-7 lines of working for the last sub-part probably differentiated the result from part (i), which was gross. This idea of 'recursive derivative formulae' is actually really cool; I'd like to see it pop up more in the exams; leads well into uni.
Overall, this was not a tough 2U paper. Some very abstract questions; less of your common setups and more tricky things that require thinking on your feet. But no super disgusting questions like we had in the early 2000's, which is what I thought we'd be up against (I'm glad I was wrong). Series seems to be the weird one this year; they took it out of the MC completely and scattered it throughout. Interesting. 22 marks for Applications of Calculus to Physical World, so that remains a huge part of the exam (this is bigger than any year in recent memory, actually).
Overall, Band cut-offs should sit steady from last year, perhaps drop ever so slightly. I did the Exam in 1.5 hours and so far, based on corrections, I got ~93% raw. This puts it roughly in line with the more recent exams. I'd personally say it was easier than 2014, but perhaps harder than 2015 :)
What do you think? ;D
Let us know your thoughts on this exam! If you notice any mistakes, please post them below... otherwise, what did you think? Good, bad? Hard? Easy?
To join the conversation, you can register for an account here if you haven't already got one ;D
Post by: noonedoesnt on October 21, 2016, 05:29:13 pm
Post by: ml125 on October 21, 2016, 05:32:03 pm
Post by: noonedoesnt on October 21, 2016, 05:33:09 pm
Post by: onepunchboy on October 21, 2016, 05:48:42 pm
Post by: rinagee12 on October 21, 2016, 05:48:49 pm
Although for me I think the 'difficult' questions just seemed that way due to pressure/stress/insufficient practice. I feel that someone who was a lot better prepared and worked really really hard would find them easy... idk
Post by: RuiAce on October 21, 2016, 05:49:37 pm
Chillaxed multiple choice is nice.
The paper didn't look too hard, but it looked really weird to me. I'll properly look at it later!
Post by: Sanaz on October 21, 2016, 05:51:18 pm
Post by: Primallis on October 21, 2016, 06:09:04 pm
Post by: RuiAce on October 21, 2016, 06:12:39 pm
Definitely have seen a lot worse but have seen better of Question 11. I guess they balanced the easier MC with the harder Question 11.I wouldn't say it's hard but probably compared to in general it was more intense. Curve sketching and a trigonometric equation lol
Post by: bananamilk9936 on October 21, 2016, 06:17:04 pm
Post by: joey9911 on October 21, 2016, 06:19:29 pm
Overall, I estimate my final external raw mark to fall somewhere between 70-80. :)
Post by: brenden on October 21, 2016, 06:22:01 pm
Post by: fizzy.123 on October 21, 2016, 06:28:59 pm
Post by: WLalex on October 21, 2016, 06:32:29 pm
shouldn't the answer to Q 6 be pi/3 (A) and not B, because the period of a tan graph is pi/b for graphs in the form a tan (bx)
I agree :) probably just forgot
Post by: MagmaMeerkat on October 21, 2016, 06:50:09 pm
Aside from that, from the answers I reckon I did okay with multiple choice!
Q15 and 16 looked difficult initially, but after a few moments starting to work through them I think it was quite smooth for me :)
Post by: brenden on October 21, 2016, 06:50:48 pm
shouldn't the answer to Q 6 be pi/3 (A) and not B, because the period of a tan graph is pi/b for graphs in the form a tan (bx)Yep, he's fixed it up. Good spot!
Post by: WLalex on October 21, 2016, 06:53:25 pm
Post by: itsAnuu on October 21, 2016, 06:53:58 pm
Post by: bcooz on October 21, 2016, 06:56:32 pm
Post by: onepunchboy on October 21, 2016, 06:58:15 pm
Post by: wesadora on October 21, 2016, 06:59:57 pm
For Q 12 d) ii) dont u divide by 3 instead of times 3
nah, you take 3 out of the brackets as a constant, then chuck it out at the front of the integral :P
Post by: onepunchboy on October 21, 2016, 07:03:34 pm
Post by: pikachu975 on October 21, 2016, 07:07:45 pm
I think 2a is wrong... shouldn't it be -10 on the top.. not sure thats just what i remember i got
Yeah it should be -10 on the numerator.
Post by: Sanaz on October 21, 2016, 07:09:37 pm
Post by: katiee1404 on October 21, 2016, 07:12:24 pm
i did 0.00425 because, correct me if i'm wrong, it didn't say how many sig fig or decimal places it needed
Post by: aashini on October 21, 2016, 07:13:17 pm
I quickly glanced at the 2U paper.
Chillaxed multiple choice is nice.
The paper didn't look too hard, but it looked really weird to me. I'll properly look at it later!
Well I screwed up multiple choice (3) and question 15c (11 and iii) and question 16 b (iii,iv)
Post by: Syndicate on October 21, 2016, 07:13:36 pm
Will I lose mark for not simplfiying 4/pi - 1/2
You shouldn't lose marks for that (unless the question stated that the answer must be rounded to certain decimal places).
Can someone explain how q8 of MC has 5 solutions (D)?
if x has a domain of [0, 2pi], then 2x has a domain of [0, 4pi]
Which means D is the correct answer as there are 5 solutions.
Post by: RuiAce on October 21, 2016, 07:17:31 pm
You shouldn't lose marks for that (unless the question stated that the answer must be rounded to certain decimal places).Note that they do not use interval notation in the HSC. You need to convert that to 0<=x<=2pi
if x has a domain of [0, 2pi], then 2x has a domain of [0, 4pi]
Which means D is the correct answer as there are 5 solutions.
Post by: Sanaz on October 21, 2016, 07:20:15 pm
As a person with Mathematics being their weakest subject, I definitely found this exam pretty okay! Some hard questions which I skipped in the exam (though came back to them at the end), and some questions which I know I got 100% correct.
Overall, I estimate my final external raw mark to fall somewhere between 70-80. :)
I totally agree! ( I suck at maths)
Post by: MysteryMarker on October 21, 2016, 07:32:24 pm
Post by: pikachu975 on October 21, 2016, 07:39:41 pm
For Q11 c) would i have lost a mark for not combining the bounds? As in leaving it as x<=5 and x>=-1?
It'd probably still be alright.
Post by: JamesMcFadden on October 21, 2016, 07:48:42 pm
Post by: ml125 on October 21, 2016, 07:54:29 pm
12aii how was this done? I think that the top line should read 15 because it was 3 +4 -22 :)Top line would be 3(1)+4(0)-22=-19
Post by: Klexos on October 21, 2016, 07:54:42 pm
For Q10 in MC, do both C and D not equal 4, like the original function does when you sub in x=1??
I actually took the time to test it out with other numbers, C doesn't work after x = 1 or x = 2
Post by: itsAnuu on October 21, 2016, 07:56:00 pm
Post by: ml125 on October 21, 2016, 07:57:22 pm
But 3 + 4 -22 doesn't equal 19?You lose the 4 because it gets multiplied by 0, it becomes 3-22=-19 Then you take absolute value, so 19.
Post by: zachary99 on October 21, 2016, 07:58:20 pm
Post by: jamonwindeyer on October 21, 2016, 07:59:31 pm
shouldn't the answer to Q 6 be pi/3 (A) and not B, because the period of a tan graph is pi/b for graphs in the form a tan (bx)
Thanks for the picking up this error first!! I'm going through the conversation to catch the rest now!!
I set myself the challenge to do it in 1.5 hours from 6-7:30, and I succeeded, but I'm expecting an algebra mistake or two ;)
Post by: jamonwindeyer on October 21, 2016, 07:59:48 pm
i cant see the answers for question 14+ .....dont know if its just my computer or....
It was me too; I just fixed it, try again! ;D
Post by: sanj123 on October 21, 2016, 08:05:08 pm
Post by: jamonwindeyer on October 21, 2016, 08:06:13 pm
Yeah it should be -10 on the numerator.
Which question are we at here? If I agree I'll fix it up! ;D
pretty sure that simpsons rule solutions is wrong
Can you give me the alternative? I think its okay but I could be wrong :)
Post by: zachary99 on October 21, 2016, 08:07:10 pm
Post by: jamonwindeyer on October 21, 2016, 08:07:24 pm
Question 13 d does not have a minus x in it
Yes it does, we need to subtract the area underneath \(y=x\) ;D
Post by: pikachu975 on October 21, 2016, 08:08:03 pm
Post by: jamonwindeyer on October 21, 2016, 08:08:31 pm
question 14 is simpsons rule, therefore it will 2/6 in front of the brackets not 2/2 :)
Ohhh thank you! I was looking at the numbers inside, must have glanced at the Trapezoidal Rule above it, thanks for the correction guys! ;D
Post by: RobotoRaccoon on October 21, 2016, 08:08:53 pm
Post by: bohimei on October 21, 2016, 08:09:24 pm
I got y = 100 eventually. idk please clear my confusion
Post by: AdrianJW on October 21, 2016, 08:12:50 pm
Post by: jamonwindeyer on October 21, 2016, 08:14:45 pm
I think b of question 11
You did the very last question wrong, you don't want when dy/dt = 0, you want when it's derivative does
Isnt the last one about maximising the rate of growth not maximising growth? I differentiated the Rate=y.....
I got y = 100 eventually. idk please clear my confusion
All good catches (especially that last one, yikes, that's what you get for rushing); fixing all of them now! :)
Post by: itsAnuu on October 21, 2016, 08:15:23 pm
Post by: hungrybubbles on October 21, 2016, 08:16:23 pm
Post by: jamonwindeyer on October 21, 2016, 08:18:18 pm
the one where you write n=11, the geometric series goes to r^n-2, so in the sum formula its r^n-1 not r^n, n=12
Also for 14cii) you are correct in finding x as 12, however you conclude saying the minimum length of fencing is 12m, whereas you must sub this into l to find the actual length
Both also correct, ta! ;D
Post by: Blissfulmelodii on October 21, 2016, 08:22:04 pm
Which question are we at here? If I agree I'll fix it up! ;D
Can you give me the alternative? I think its okay but I could be wrong :)
the -10 in the numerator is for 11b. I myself just did the question and i got -10/(3x-4)^2
Post by: jamonwindeyer on October 21, 2016, 08:22:34 pm
the -10 in the numerator is for 11b. I myself just did the question and i got -10/(3x-4)^2
Have already corrected this and will upload in the next batch! ;D
Post by: Blissfulmelodii on October 21, 2016, 08:26:54 pm
Have already corrected this and will upload in the next batch! ;D
ok cool :)
I feel as if the difficulty in this paper begins around question 14 onwards. Does anyone else agree?
Post by: pikachu975 on October 21, 2016, 08:27:19 pm
Post by: browny2409 on October 21, 2016, 08:35:56 pm
Also.. I can't see any working for Qtn 15 c (all parts) in the solutions ?? Is this just me?
Post by: itsAnuu on October 21, 2016, 08:38:16 pm
Post by: kimmie on October 21, 2016, 08:40:14 pm
Post by: browny2409 on October 21, 2016, 08:41:49 pm
For the last part, dont you need to find the time when y = 100 and sub it back into the original y, cause i got y = 100 and i did so much other shit,
the question asked for the population, which is given by y, so y=100 is the answer so need to do any further substitution
Post by: jamonwindeyer on October 21, 2016, 08:44:00 pm
so what do you guys think the cut off would be for a band 6?
This year I reckon it will be pretty similar to whatever it was last year; this paper didn't throw any major surprises. It was about 85 from last year, so I reckon you could lose about 15 marks and still get the Band 6 :)
Thanks for the corrections guys! My aim was always to get a 90/100 set of solutions to you in 1.5 hours, then let you help me get to 100, the faster the better I thought! ;D I think what is there has implemented all the corrections I've received, let me know if you spot more now :)
Post by: Klexos on October 21, 2016, 08:47:12 pm
Post by: jamonwindeyer on October 21, 2016, 08:48:16 pm
For 2 marks I doubt it - probably one for differentiating and one for getting y=100 I think it will be alright
Also.. I can't see any working for Qtn 15 c (all parts) in the solutions ?? Is this just me?
15C is there for me, but woops! 14 D and E aren't, will fix that now ;D
Post by: ml125 on October 21, 2016, 08:55:13 pm
Post by: itsAnuu on October 21, 2016, 08:57:20 pm
For question 11) f) I found the gradient at that point and then found the equation of the tangent because i didnt read the question. Will I still get the mark? I still wrote m=1.17
Yes you will get it
Post by: pikachu975 on October 21, 2016, 09:00:24 pm
dy/dt = y/2 - y^2 / 400
Differentiate to get:
1/2 - y/200 = 0
100 - y = 0
y = 100
Post by: lha on October 21, 2016, 09:01:49 pm
Post by: zachary99 on October 21, 2016, 09:01:57 pm
Post by: jamonwindeyer on October 21, 2016, 09:02:44 pm
Pretty sure 15ciii should be h=y/x(http://uploads.tapatalk-cdn.com/20161021/9d833781d05fb47276f5f4885e415563.jpg)
Woops! I'd already fixed that, image didn't change, should work now could you confirm? ;D
Post by: jamonwindeyer on October 21, 2016, 09:04:10 pm
For question 11) f) I found the gradient at that point and then found the equation of the tangent because i didnt read the question. Will I still get the mark? I still wrote m=1.17
Hey spagget, you could get 1/2, one of the marks would likely be for correct form, but we can't be sure until we see the criteria ;D
Post by: jamonwindeyer on October 21, 2016, 09:04:57 pm
For the last question, wouldn't expanding first be easier?
dy/dt = y/2 - y^2 / 400
Differentiate to get:
1/2 - y/200 = 0
100 - y = 0
y = 100
Good spot! That would have been easier (I'm a glutton for punishment) ;)
Post by: ml125 on October 21, 2016, 09:05:53 pm
Woops! I'd already fixed that, image didn't change, should work now could you confirm? ;DYep, works now haha ;D
Post by: itsAnuu on October 21, 2016, 09:06:16 pm
Post by: jamonwindeyer on October 21, 2016, 09:06:54 pm
For question 12c), does it matter how we got the answer? Just as long aa we used a method to get the right answer? Or did we have to use cosine rule?
Cosine was the easiest (I think), but if you get the correct answer thats fine! ;D
um, i have a concern with Q15b ii) ----------- inside the bracket (opening line) isnt it 1-(7/8)^n...........why did you have 1-(7/8)^(n-1)
Initial version of the answers had me falling for this too; there are only (n-1) terms in the series (just how like when you need it to finish before the 4th game, there are 3 terms) ;D
Post by: itsAnuu on October 21, 2016, 09:08:06 pm
Post by: jamonwindeyer on October 21, 2016, 09:08:44 pm
Hey! For that dice question, how many marks would I lose for finding n = 11 and in the formula using r to the power of n, instead of r to the power of n-1
1 :)
Just for the record, everyones corrections put my mark down to about 93/100, if it gets to 90 you all win ;)
Post by: lha on October 21, 2016, 09:09:02 pm
Post by: browny2409 on October 21, 2016, 09:09:21 pm
Also RE Qtn 16 b ii - isn't the range 10≤y<200 given that you found y=10 when t=0 and t has to be greater than zero??
Post by: ml125 on October 21, 2016, 09:11:25 pm
Also RE Qtn 16 b ii - isn't the range 10≤y<200 given that you found y=10 when t=0 and t has to be greater than zero??Yeah pretty sure it's 10≤y<200
Post by: jamonwindeyer on October 21, 2016, 09:13:20 pm
And also, for calculating the distance traveled by the particle, For |2t - 4ln(t+1)|, l let it accidentally be 2t + 4ln(t+1), my other integral of above the x-axis was correct tho. How many marks would I lose for this as I ended up getting answer wrong
Hmm, that's a tough one. It would either be one mark or two marks lost. It shows a conceptual miss, OR an algebraic error, depending on how you look at it. I'm not sure ;D
Post by: itsAnuu on October 21, 2016, 09:17:44 pm
Post by: jamonwindeyer on October 21, 2016, 09:19:26 pm
Yeah pretty sure it's 10≤y<200
LOL, that one was correct, but I've added a bracket or something to the back and it looks like zero. No idea what happened there. I'll tidy it up! ;D
Last one sorry :'D. For 14d, would I get 1 mark for summing the series at least?
Yep! ;D
Post by: MysteryMarker on October 21, 2016, 09:22:40 pm
Post by: Bilsin on October 21, 2016, 09:22:59 pm
Post by: jamonwindeyer on October 21, 2016, 09:24:22 pm
For Q 14 e, I had 9log32, so i had different integers for a and b. This still yields the correct answer but just curious as to whether strictly 45log2 is correct. Also could you explain to me why n=12 for question 15b.
Your version is correct as well! They'd accept both.
Did you sum 'n' terms, or 'n-1' terms? It's supposed to be 'n-1', I made the mistake too ;D
Post by: itsAnuu on October 21, 2016, 09:27:50 pm
Post by: bobby shmurda on October 21, 2016, 09:28:38 pm
Post by: samsam0001 on October 21, 2016, 09:29:01 pm
Post by: Lockyb98 on October 21, 2016, 09:37:40 pm
Thanks for being so quick on the paper and answer upload!
Post by: Lockyb98 on October 21, 2016, 09:45:53 pm
For Q 14 a) shouldn't the simpsons rule be h/3 (first + last + 4(0dd) + 2(even) )?
Some schools/classes learn different methods... I did the method you stated and got Jamon's answer still :)
Post by: jamonwindeyer on October 21, 2016, 09:47:37 pm
Predictions on what a raw 88 will scale to? :)
Low 90's ;D
what would be a band 5 cut off
Maybe the low 70's/high 60's? I don't have any recent data there, but 2009's was about 60-62, and we've gotten easier since then, so likely to be higher ;D
Post by: jamonwindeyer on October 21, 2016, 09:49:37 pm
For Q 14 a) shouldn't the simpsons rule be h/3 (first + last + 4(0dd) + 2(even) )?
As Locky mentioned, both work! I actually learned your rule, but I made a mental note to use what was on the formula sheet in my answers ;D
For Q12 d) (ii) - since you multiply by 3 to get it into the form required, would you not then have to multiply by 1/3 to cancel it out? So it would become 1/3 (integral from 0 -> 2 of) e^3x (1 + 3x)?
Thanks for being so quick on the paper and answer upload!
No worries! Not quite; I've pulled a factor of 3 out of the integral in their question, \((3+9x)=3(1+3x)\) ;D
Post by: itsAnuu on October 21, 2016, 09:50:00 pm
Low 90's ;D
But an 86 scaled to 90 in 2014 which was an easy year :(((
Post by: Lockyb98 on October 21, 2016, 09:51:56 pm
[/quote]
Ah yep, I see that now. Thanks!
Post by: jamonwindeyer on October 21, 2016, 09:53:52 pm
Summary
- Not too difficult, easier than 2014, harder than 2015 (imo)
- Formula sheet didn't spike the difficulty like I thought it would (phew). On the contrary, it turned about a third of these marks into substitution questions.
- Lots of Apps of Calculus, nearly a quarter of your mark
Post by: itsAnuu on October 21, 2016, 09:53:59 pm
Post by: jamonwindeyer on October 21, 2016, 09:56:12 pm
Would you need to pull the factor out or can you go straight to 3xe^x and say (x3 due to the integral being multiplied by 3) for 2 marks
That works too! ;D
Post by: ehatton2016 on October 21, 2016, 09:56:41 pm
You haven't included answers for Qtn 14 D and E
Also RE Qtn 16 b ii - isn't the range 10≤y<200 given that you found y=10 when t=0 and t has to be greater than zero??
Agreed!!
Would I drop a mark if I put 10<y<200 instead of 10</=y<200?? flipping out
Post by: itsAnuu on October 21, 2016, 09:58:45 pm
Agreed!!
Would I drop a mark if I put 10<y<200 instead of 10</=y<200?? flipping out
Yes :(
Post by: ehatton2016 on October 21, 2016, 09:59:12 pm
Post by: jamonwindeyer on October 21, 2016, 10:00:50 pm
Agreed!!
Would I drop a mark if I put 10<y<200 instead of 10</=y<200?? flipping out
I think the equals is sort of debatable; like, the function is valid after the Yabbies were introduced, meaning for \(t>0\). Perhaps I'm misinterpreting there, uni has taught me to be pedantic over when functions are valid. I'm reasonably sure they would pay you for it either way :P
Post by: jamonwindeyer on October 21, 2016, 10:02:07 pm
Confused why Q4 is A and not B, because isn't be just a cubic, y=x3, so its odd?
Cubics are only odd when they are centred on the origin! EG: y=x^3+4 (which could be what was shown) is not odd. You need rotational symmetry about the origin; that's the sine wave in A ;D
Post by: ehatton2016 on October 21, 2016, 10:06:17 pm
Post by: pikachu975 on October 21, 2016, 10:07:14 pm
I've added some commentary below the solutions if anyone is interested about what I thought about the exam!
Summary
- Not too difficult, easier than 2014, harder than 2015 (imo)
- Formula sheet didn't spike the difficulty like I thought it would (phew). On the contrary, it turned about a third of these marks into substitution questions.
- Lots of Apps of Calculus, nearly a quarter of your mark
Not really sure, I found it harder than 2014 and 2015 by a lot because I've done lots of past papers but never seen like 2 of those multiple choice before and the yabby question was really tricky, so was the probability with the wording.
Post by: jamonwindeyer on October 21, 2016, 10:07:40 pm
What will a 95-98 scale to?? or does it stay the same?
Might shift up a point or two in that range, but nothing excessive! ;D
Post by: itsAnuu on October 21, 2016, 10:08:40 pm
What will a 95-98 scale to?? or does it stay the same?
96-99
Post by: fizzy.123 on October 21, 2016, 10:11:16 pm
Post by: jamonwindeyer on October 21, 2016, 10:13:10 pm
Not really sure, I found it harder than 2014 and 2015 by a lot because I've done lots of past papers but never seen like 2 of those multiple choice before and the yabby question was really tricky, so was the probability with the wording.
I think what was difficult this year wasn't like, the absolute level of 'hardness' of the questions. Because examined in isolation, they are not terrible. But collectively the paper is different, that's for sure, and that definitely throws a spanner in the works ;D
Post by: jamonwindeyer on October 21, 2016, 10:14:53 pm
what will a raw mark of 80 scale up to?
Higher 80's, just shy of 90 probably :)
Post by: pikachu975 on October 21, 2016, 10:24:57 pm
Post by: wesadora on October 21, 2016, 10:27:00 pm
pretty good paper overall tho :)
also didn't notice for the die rolling it had to be (7/8)^n-1 not just (7/8)^n -_______- tricky.......
Post by: jamonwindeyer on October 21, 2016, 10:27:59 pm
With my expanding method for the yabbies to get y = 100, if I didn't test or show nature would I lose a mark?
The thing that confuses me here is that there is 2 marks allocated; thats low. Further, earlier in the exam, they specifically asked for justification (a first). So I think you'd be okay! :)
Post by: kb123 on October 21, 2016, 10:28:11 pm
Post by: jamonwindeyer on October 21, 2016, 10:30:24 pm
so that's how Q9 works... i was so confused
Was probably the strangest of the Multiple Choice ;D
Post by: kb123 on October 21, 2016, 10:32:18 pm
Post by: kb123 on October 21, 2016, 10:34:10 pm
I just used axis of symmetry since dy/dt is a quadratic, instead of differentiating it. Much easier.
Post by: pikachu975 on October 21, 2016, 10:36:11 pm
Was probably the strangest of the Multiple Choice ;D
Yeah gg I calculated the height of one of the triangles wrong so I got the wrong area....
Post by: kb123 on October 21, 2016, 10:37:21 pm
Yeah gg I calculated the height of one of the triangles wrong so I got the wrong area....
I just took the integral disregarding the absolute value lol
Post by: jamonwindeyer on October 21, 2016, 10:38:03 pm
For Q 16 b (iv)
I just used axis of symmetry since dy/dt is a quadratic, instead of differentiating it. Much easier.
Ahhhh clever clever!! ;D
for Q16 (a) (iv), how does the absolute value part work?
Basically the area in that section yields a negative, but we don't want that! So we just take the same thing, but positive :)
Post by: pikachu975 on October 21, 2016, 10:43:26 pm
I just took the integral disregarding the absolute value lol
Yeah I don't get why this didn't work to be honest.
Edit: Nvm
Post by: kb123 on October 21, 2016, 10:44:16 pm
Ahhhh clever clever!! ;D
Basically the area in that section yields a negative, but we don't want that! So we just take the same thing, but positive :)
Oh ok...
Post by: bohimei on October 21, 2016, 10:54:20 pm
Post by: MysteryMarker on October 21, 2016, 10:58:48 pm
Your version is correct as well! They'd accept both.
Did you sum 'n' terms, or 'n-1' terms? It's supposed to be 'n-1', I made the mistake too ;D
Why is it 'n-1' terms? Sorry, just really curious as to how i didn't see this.
Post by: wesadora on October 21, 2016, 11:03:55 pm
Why is it 'n-1' terms? Sorry, just really curious as to how i didn't see this.bruh... I made that mistake. because you worked out in part one for FOUR rounds, and proved that it was a series with THREE terms.
therefore for n rounds, there are n-1 terms.
Post by: wesadora on October 21, 2016, 11:07:19 pm
How would a raw 90 scale this year you guys reckon?probably 93-94... not much of a difference 90+ and above raws
Post by: $Billi$ on October 21, 2016, 11:08:14 pm
Post by: SaeedAyman on October 21, 2016, 11:14:02 pm
Post by: $Billi$ on October 21, 2016, 11:18:57 pm
How much do you guys think a raw mark of 86 will go up to considering my school will have atleast 3 people with 98+? Rank is really good too (rank 6)? Is there a chance for a 90 or higher?
around 89 or 90 if you're lucky
Post by: fizzy.123 on October 21, 2016, 11:46:18 pm
Post by: jamonwindeyer on October 21, 2016, 11:54:14 pm
How much do you guys think a raw mark of 86 will go up to considering my school will have atleast 3 people with 98+? Rank is really good too (rank 6)? Is there a chance for a 90 or higher?
None of those things impact the way your raw mark is handled; your HSC mark is you and just you. That said I reckon you should crack 90 with a raw mark like that ;D
Post by: jamonwindeyer on October 21, 2016, 11:54:44 pm
Do you lose marks for not righting the units, e.g. units^2 or units^3 for volume?
Ehhh, probably not if you've done everything else right, but I'm not 100% sure there :)
Post by: jamonwindeyer on October 21, 2016, 11:55:56 pm
other than the probability question (n-1) I've got everything right! so 99 raw mark 8) I hope extension 1 is as easy as this
Great work! Although I wouldn't say this was"easy", I reckon you are just super good at Math ;)
Post by: dazatoN on October 22, 2016, 12:47:09 am
also, for 15a, if the limits were wrong when integrating and you - instead of +, how many marks do you reckon il lose?
Post by: jamonwindeyer on October 22, 2016, 01:00:54 am
For 13 ii, if you correctly labelled all the points but drew the graph without showing how a horizontal point of inflexion looks, would u lose a mark?
also, for 15a, if the limits were wrong when integrating and you - instead of +, how many marks do you reckon il lose?
f you indicated it as a horizontal inflexion in the previous part, and you showed the correct gradient pattern on the graph, you'd be all set ;D it doesn't have to be super pronounced :) a little error like that would lose a single mark! :)
Post by: Primallis on October 22, 2016, 08:17:16 am
Post by: olivercutbill on October 22, 2016, 08:49:20 am
(1+2+3+...+9)log2 and not convert to 45log2
anyway, seems fine - I think a mark of 89/90 by those answers.
Post by: lha on October 22, 2016, 09:13:14 am
Your version is correct as well! They'd accept both.
Did you sum 'n' terms, or 'n-1' terms? It's supposed to be 'n-1', I made the mistake too ;D
For the log question i got 9/2 log1024
Is that correct as well?
Post by: FallonXay on October 22, 2016, 09:21:22 am
For the log question i got 9/2 log1024
Is that correct as well?
I think you'd have to simplify it to 9ln(32) --> (then possibly 45ln2)since the question specified that a and b were integers i.e not fractions (IIRC)
Post by: lha on October 22, 2016, 09:23:12 am
I think you'd have to simplify it to 9ln(32) since the question specified that a and b were integers i.e not fractions (IIRC)
Would I lose full marks?
Post by: FallonXay on October 22, 2016, 09:24:39 am
Would I lose full marks?
I'd say you might get 1 mark for the working? But lose one for not having integers? (I'm not too sure, sorry - maybe someone else could answer :) )
Post by: RuiAce on October 22, 2016, 09:26:08 am
(10 pages is too much scrolling haha)
Post by: FallonXay on October 22, 2016, 09:27:43 am
Alright. I lost my sanity yesterday over those 4U solutions so I didn't really participate here. How did us 2U guys find it in general?
(10 pages is too much scrolling haha)
Haha, nice work :p
Imo I didn't find the test too difficult - though there were a variety of questions that were quite different to previous years; few tricks here and there.
Post by: lha on October 22, 2016, 09:27:53 am
Alright. I lost my sanity yesterday over those 4U solutions so I didn't really participate here. How did us 2U guys find it in general?
(10 pages is too much scrolling haha)
Hard :( but everyone else says that it was actually easy...
Post by: RuiAce on October 22, 2016, 09:30:33 am
Haha, nice work :pThanks :P
Imo I didn't find the test too difficult - though there were a variety of questions that were quite different to previous years; few tricks here and there.
And that's good to hear (y)
Yeah, having only glanced at the paper I can tell that there were definitely tricks floating around. I still need to find the time (and energy, poor sleeping patterns right now) to properly read through the paper.
Hard :( but everyone else says that it was actually easy...Well I mean, like I said at first glance it seems like the paper got weirder. A paper that's weirder is full of confusing wording.
Tbh I'd say most people who found it hard were hit by a stroke of misfortune in being unable to decode the questions at times.
So long as you guys performed at the best of your abilities :)
Post by: pikachu975 on October 22, 2016, 09:36:38 am
Alright. I lost my sanity yesterday over those 4U solutions so I didn't really participate here. How did us 2U guys find it in general?
(10 pages is too much scrolling haha)
I think it was decently hard, the multiple choice had questions I haven't seen, no financial question this year. The probability and last question were a bit tricky.
Would I lose a mark on the last question for just deriving then solving to get y = 100 but not showing it's a maximum? I thought I didn't need to since it was 2 marks only.
Post by: RuiAce on October 22, 2016, 09:42:55 am
I think it was decently hard, the multiple choice had questions I haven't seen, no financial question this year. The probability and last question were a bit tricky.MC don't look too bad. I still remain on they look weirder because I didn't expect to see that, but I don't see a difficulty spike.
Would I lose a mark on the last question for just deriving then solving to get y = 100 but not showing it's a maximum? I thought I didn't need to since it was 2 marks only.
That probability required a G.P.
This HAS appeared in the past before... however it is certainly at the upper end of what they can ask you in probability. Not every probability question collapses into a G.P. but there have been quite a few now that have. That would be targeting band 6 though.
Pretty sure showing a maximum was necessary but you may want to ask Jamon since he wrote the answers.
Post by: FallonXay on October 22, 2016, 09:44:44 am
I think it was decently hard, the multiple choice had questions I haven't seen, no financial question this year. The probability and last question were a bit tricky.
Yeah, the (usually) annuities series question was dealing with a gardener and harmful insects as opposed to finances. Freaked me out a little during reading time but then I realised it was basically just similar to a normal annuities question :)
Post by: RuiAce on October 22, 2016, 10:06:02 am
Yeah, the (usually) annuities series question was dealing with a gardener and harmful insects as opposed to finances. Freaked me out a little during reading time but then I realised it was basically just similar to a normal annuities question :)I'll look at the paper at 12-ish. Hopefully then I can join in the fuss haha
Post by: jamonwindeyer on October 22, 2016, 10:46:04 am
I think you'd have to simplify it to 9ln(32) --> (then possibly 45ln2)since the question specified that a and b were integers i.e not fractions (IIRC)
This is correct; lha I think you'd lose the mark for not fully simplifying your expression as required; but you'd definitely get 1 out of the 2! :)
Yeah, the (usually) annuities series question was dealing with a gardener and harmful insects as opposed to finances. Freaked me out a little during reading time but then I realised it was basically just similar to a normal annuities question :)
Precisely! Mutton dressed as lamb ;)
I think it was decently hard, the multiple choice had questions I haven't seen, no financial question this year. The probability and last question were a bit tricky.
Would I lose a mark on the last question for just deriving then solving to get y = 100 but not showing it's a maximum? I thought I didn't need to since it was 2 marks only.
Normally I'd say yes, but earlier in the paper it specifically asked for a justification of a maximum. This has never been done before, so it makes me change my mind to say that they wouldn't mark you down for not proving it (though proving it would have been nice) ;D we'll have to wait until they release the marking criteria until we know for sure :) :) :)
Post by: treesap on October 22, 2016, 11:07:49 am
Post by: olivercutbill on October 22, 2016, 11:10:48 am
This is correct; lha I think you'd lose the mark for not fully simplifying your expression as required; but you'd definitely get 1 out of the 2! :)
Precisely! Mutton dressed as lamb ;)
Normally I'd say yes, but earlier in the paper it specifically asked for a justification of a maximum. This has never been done before, so it makes me change my mind to say that they wouldn't mark you down for not proving it (though proving it would have been nice) ;D we'll have to wait until they release the marking criteria until we know for sure :) :) :)
I would get 1/2 for leaving my answer as:
(1+2+3+...+9)log2
right?
Post by: jamonwindeyer on October 22, 2016, 11:12:17 am
Is it me or does anyone else feel like Q11)e) wasn't in their exam booklets?
Hey! Welcome to the forums! Unfortunately, it was definitely there; a missing page is absolutely plausible (but highly unlikely), but a single missing question isn't really feasible. It's all good, it was only 3 marks! :)
Post by: jamonwindeyer on October 22, 2016, 11:13:34 am
I would get 1/2 for leaving my answer as:
(1+2+3+...+9)log2
right?
Yeah for sure!! ;D you were on the right track; 1 out of 2 for sure :)
Post by: treesap on October 22, 2016, 11:19:46 am
Post by: jamonwindeyer on October 22, 2016, 11:30:50 am
Would you lose a mark in the curve sketching of 13)a)ii) when you don't label the x intercept at X=4?
I think so; it did say to label all intercepts so I think you'd lose a mark unfortunately :P
Post by: alexisastupidn on October 22, 2016, 11:59:17 am
Post by: treesap on October 22, 2016, 12:17:34 pm
Post by: captcha on October 22, 2016, 12:23:39 pm
Post by: itsAnuu on October 22, 2016, 01:04:17 pm
Post by: treesap on October 22, 2016, 01:12:44 pm
Post by: itsAnuu on October 22, 2016, 01:14:43 pm
Post by: bohimei on October 22, 2016, 02:13:45 pm
Post by: akash6969 on October 22, 2016, 02:20:00 pm
Post by: $Billi$ on October 22, 2016, 02:24:05 pm
Post by: treesap on October 22, 2016, 02:56:22 pm
Post by: jamonwindeyer on October 22, 2016, 04:52:19 pm
why did you change 15 a to 56pi/3? shouldn't it be 40pi/3? the y is already squared you dont have to sqaure the 9 again! it's 1/9 not 1/81. but please correct me if im wrong.
Hey! Woops, sorry about that, must have had a version cross when editing the formatting this morning; managed to upload one of my first versions of the solutions from prior to upload; just changed it back! Sorry for confusion ;D
Question 15a is incorrect, for whatever reason you decided to square root the curves, and in doing so took out 1/9 but you didnt square root this. If you are going to do this method it should be 1/3 outside the sqrt(36-4x^2). Although I dont know why you have done this in the first place, we are asked for volume which requires y^2 anyway.
Technically, to perform a volume of revolution you should consider a function; which these aren't. To be most correct I first considered only the top half of \(C_1\) and \(C_2\), and then squared these in the formula. You are right, it gives the same result though! They wouldn't have enforced this in the HSC marking mind you, just going straight to \(y^2\) and \(x^2\) is definitely okay too :)
Good catch on the intermediate error though; I'll tidy that up for sure! But the answer is correct (as of the edit I've just made, again, sorry for the confusing version cross) :)
Post by: becryan on October 23, 2016, 10:40:40 am
Post by: jamonwindeyer on October 23, 2016, 11:56:27 am
What would a 79 raw mark scale to?
Welcome to the forums!! ;D Probably the mid 80's? Your best source for trends in previous years is here ;D
Post by: WLalex on October 23, 2016, 02:52:42 pm
I was wonder if you could enlighten me on how our internal mark/rank from the school will influence your overall HSC mark that we get (the one the determines which band we get etc) e.g. like if it will increase or decreased based on our rank from school or what not
Post by: RuiAce on October 23, 2016, 03:04:37 pm
Hey Jamon, or whoever else :PYour external marks influence your internals. Not vice versa.
I was wonder if you could enlighten me on how our internal mark/rank from the school will influence your overall HSC mark that we get (the one the determines which band we get etc) e.g. like if it will increase or decreased based on our rank from school or what not
Once moderation has happened and your internals are adjusted, after some alignment you get your overall HSC marks.
Scaling guide by Jamon
Post by: bugsbuggy on October 25, 2016, 07:21:19 pm
Post by: RuiAce on October 25, 2016, 07:25:03 pm
Hey everyone! i'm looking at 88 internal and 87-90 for the hsc. would that align to a band 6 by any chance? Thanks in advance!In saying that I completely disregarded your internal mark because moderation hasn't happened yet.
As for your externals, from the raw marks database it is clear that in general, 87 raw aligns to 90 or 91.
Post by: CC2095 on October 28, 2016, 09:09:25 am
You have 10<y<200
should be 10<=y<200
Post by: CC2095 on October 28, 2016, 09:13:40 am
denominator should be 3x - 4 not 3x + 4
Post by: jamonwindeyer on October 28, 2016, 10:48:23 am
Question 16B
You have 10<y<200
should be 10<=y<200
I'm leaving this one as it is, because the question says the function is valid after the yabbies are introduced. Speaking strictly this excludes \(t=0\). I'm probably reading too far into the question, but yeah, I'll leave it for now. Not a huge deal ;D
Q11b
denominator should be 3x - 4 not 3x + 4
Touche! I'll fix this up today, good spot ;D
Welcome to the forums! :)