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Archived Discussion => VCE Exam Discussion 2019 => Exam Discussion => Victoria => VCE Maths Exams => Topic started by: Joseph41 on October 22, 2019, 01:52:47 pm

Title: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Joseph41 on October 22, 2019, 01:52:47 pm
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Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: AlphaZero on November 07, 2019, 11:49:40 pm
And now, after some absolutely embarrassing derps on my end, with just a bit of luck...

SPECIALIST EXAM 1 SOLUTIONS
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: crouchie on November 08, 2019, 05:35:43 am
If you've been on the Methods exams discussion threads, you probably know what this post is for.

Our solutions will be up as soon as possible.

I have my own uni exams very soon (first one Monday lol), so I'm probably just going to write the solutions by hand instead of TeX-ing them since I don't exactly have an amazing amount of free time on my hands.

Best of luck tomorrow!  ;D

Great stuff mate. Looking forward to your well written solutions as always!
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Tau on November 08, 2019, 10:52:59 am
I thought the exam was pretty good, some interesting sorts of questions, but fairly decent.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Alexmaths on November 08, 2019, 10:58:01 am
Really had trouble showing the forces one and getting the last question in the correct form, but other than that everything else seemed fine.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: AnonymooseUser on November 08, 2019, 10:58:14 am
Does anyone remember if question 5 asked for intersection points to be labelled, or just endpoints and turning points?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Eric Dong on November 08, 2019, 10:59:23 am
 :D concerning Maths tutor XD. Questions turned out to be a bit unexpected compared to the last few years’. How did you guys find it? A+ cut off ? 35?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Purple_Mango on November 08, 2019, 11:01:22 am
Does anyone remember if question 5 asked for intersection points to be labelled, or just endpoints and turning points?

Only endpoints and turning points, I'm pretty sure
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: futuredoc on November 08, 2019, 11:10:42 am
What score should I aim for in exam 2 with an A (32-33/40) on exam 1 for a raw 40? Is it even still possible (given I'm top 20% of strong cohort)?
Felt like I really screwed up exam 1 :((
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: justaloser on November 08, 2019, 11:15:58 am
Really had trouble showing the forces one and getting the last question in the correct form, but other than that everything else seemed fine.

I heard from my friends that you weren't supposed to rationalise your fractions in order to get it into the correct form. Regardless, I think that they'll still award 3 or 4 marks if you only have difficulty with writing the answer in the form.

Does anyone remember if question 5 asked for intersection points to be labelled, or just endpoints and turning points?


Yep, just endpoints and turning points.

---

I thought this exam wasn't too bad. Is the general consensus that it was slightly harder than last year's? Nevertheless, the fact that there was only 3 marks (with 3 1-mark questions) for probability suggests that there'll be a lot more of probability/statistics on Exam 2.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: AlphaZero on November 08, 2019, 11:25:39 am
Solutions are up!

Managed to get them up before the thread made two pages eyy


Edit: lol guess not
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: studyingg on November 08, 2019, 11:27:40 am
Solutions are up!

Managed to get them up before the thread made two pages eyy

I think you forgot to include the last page, thank you so much though!! :))
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: ss96684 on November 08, 2019, 11:33:13 am
Thanks.
I think you have made an error on 9a.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: AnonymooseUser on November 08, 2019, 11:35:35 am
What score should I aim for in exam 2 with an A (32-33/40) on exam 1 for a raw 40? Is it even still possible (given I'm top 20% of strong cohort)?
Felt like I really screwed up exam 1 :((


I got ~29/40 for exam 1 in methods - sometimes these things happen so try not to beat yourself up. Based on the twm distributions from last year I would estimate very roughly ~93% for exam 2 for a raw 40. All you can do at this stage however is move on and focus on doing your best - exam 2 is worth double exam 1!

--

Do you think I would lose a mark for 7c for writing 6+6k, instead of just 6k. Don't know what I was thinking.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Tau on November 08, 2019, 11:36:06 am
Solutions are up!

Managed to get them up before the thread made two pages eyy

Btw, Question 3 doesn’t actually specify that h is normally distributed.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: undefined on November 08, 2019, 11:38:18 am
If I forgot to put pi in the revolution formula and my answer was correct without the multiplied pi, would I lose 4 marks?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: jac0016 on November 08, 2019, 12:09:15 pm
Where do I get a copy of the actual exam?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Macnamat on November 08, 2019, 12:15:55 pm
Since question 9a asked for the tension in the string, wouldn’t it actually be mg/sin(a)?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Tau on November 08, 2019, 12:42:23 pm
Since question 9a asked for the tension in the string, wouldn’t it actually be mg/sin(a)?


There are two ‘components’ there, each with magnitude T Newtons, so you resolve vertically and you get 2(T*sin(alpha)) is balanced by the weight force. Dividing through by 2sin (alpha) gives the required result for T.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: S_R_K on November 08, 2019, 12:53:11 pm
Slightly offbeat exam. Question 1 seemed surprisingly difficult for a Q1, requiring both separation of variables and substitution; and then Q2 was very easy. Q 3c was unnecessary in light of 3a; it almost felt like they discovered late that they had a 39 marker and needed to find a mark somewhere. Q5 felt more like a Methods question; 5b very easy, most likely examiners will be very picky about positioning of endpoints / turning points on the scale. Qs 6–8 pretty standard. Q9 b was good, requiring both resolution of forces and a trig-identity. Q10 was silly, apart from the first few steps it's just assessing how fast you can do Year 10 maths, not whether your understanding of the study design is in the top 10% of the state.

The exam was more noteworthy for what it didn't include: partial fractions and arc length, which really should be on exam 1, because they are trivialised by CAS.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Tau on November 08, 2019, 12:59:15 pm
Slightly offbeat exam.

Definitely agree - interesting choices in questions and I also felt it strange they neglected arc length and partial fractions.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Tau on November 08, 2019, 01:00:43 pm
If I forgot to put pi in the revolution formula and my answer was correct without the multiplied pi, would I lose 4 marks?

I can’t imagine you’d lose 4 marks for that, at most they could take off 2 - 1 for incorrect expression for volume, 1 for wrong final answer. Most likely you’d only lose 1 mark.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: studyingg on November 08, 2019, 01:02:49 pm
Slightly offbeat exam. Question 1 seemed surprisingly difficult for a Q1, requiring both separation of variables and substitution; and then Q2 was very easy. Q 3c was unnecessary in light of 3a; it almost felt like they discovered late that they had a 39 marker and needed to find a mark somewhere. Q5 felt more like a Methods question; 5b very easy, most likely examiners will be very picky about positioning of endpoints / turning points on the scale. Qs 6–8 pretty standard. Q9 b was good, requiring both resolution of forces and a trig-identity. Q10 was silly, apart from the first few steps it's just assessing how fast you can do Year 10 maths, not whether your understanding of the study design is in the top 10% of the state.

The exam was more noteworthy for what it didn't include: partial fractions and arc length, which really should be on exam 1, because they are trivialised by CAS.

Do you think the A+ cut-off would be comparable to the 2016 grade distribution or 2017&2018? 
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Macnamat on November 08, 2019, 01:08:59 pm
There are two ‘components’ there, each with magnitude T Newtons, so you resolve vertically and you get 2(T*sin(alpha)) is balanced by the weight force. Dividing through by 2sin (alpha) gives the required result for T.

Might’ve done this wrong but aren’t we solving for 2T since each component is T?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: S_R_K on November 08, 2019, 01:24:58 pm
Do you think the A+ cut-off would be comparable to the 2016 grade distribution or 2017&2018?

No idea, really. Even though it wasn't conceptually challenging, there were enough quirks and hurdles to throw students off.

I doubt it will be lower than the last couple of years.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: undefined on November 08, 2019, 01:31:31 pm
I can’t imagine you’d lose 4 marks for that, at most they could take off 2 - 1 for incorrect expression for volume, 1 for wrong final answer. Most likely you’d only lose 1 mark.
Thank you. Was really scared that I'd lose 4 marks for forgetting one tiny thing.

No idea, really. Even though it wasn't conceptually challenging, there were enough quirks and hurdles to throw students off.

I doubt it will be lower than the last couple of years.
I think it will be around 34-35/40. It got progressively harder (especially the last 2 questions) compared to 2018, which remained at a consistent difficulty throughout in my opinion. The marks where I see people losing are 9b, maybe 2 marks for q10 and the variance question.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Jadu on November 08, 2019, 01:58:46 pm
Too easy.

I wish they made it harder

Its a 40/40 for me ;D :D ;)
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Lachlanmartino19 on November 08, 2019, 03:03:53 pm
I wrote natural numbers {1,2,3...} instead of integers for the questions 7c and d but had the same formulas do you think i would achieve any marks from that?? :'(
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Jackson.Sprigg on November 08, 2019, 03:09:59 pm
I wrote natural numbers {1,2,3...} instead of integers for the questions 7c and d but had the same formulas do you think i would achieve any marks from that?? :'(

Don't think so as it was only worth one mark and stating N instead of Z excludes a lot of possibilities :(
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Ali Ali on November 08, 2019, 03:15:27 pm
Must say I'm very disappointed with this year's exam. Felt like they weren't giving the high achievers a chance to distinguish themselves with engaging problems, instead just throwing a whole load of algebra at you hoping that you screw up somewhere in there. To be honest, I think anyone could have gotten a 40/40 on a good day for this one since mistakes in algebra can happen to anyone. Personally had a few algebra mistakes (2 marks down first question possibly since i forgot to include the 1 in 1 + e^2x inside the second log, 2 marks down in probability due to brain slightly failing)  but still managed better than some friends who are very good at the subject but just made a few more algebra mistakes.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Alexmaths on November 08, 2019, 03:17:04 pm
Would I still get the mark if I had n=-6k; k is an element of Z for the real solutions question? It still works right?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: AlphaZero on November 08, 2019, 03:28:37 pm
Would I still get the mark if I had n=-6k; k is an element of Z for the real solutions question? It still works right?

Yep, it's equivalent. You would get the mark.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Jackson.Sprigg on November 08, 2019, 03:34:33 pm
Must say I'm very disappointed with this year's exam.

Likewise. That last question was ridiculous, after the initial implicit diff what even was the point in it? I ended up not even fully simplifying it as there just wasn't enough space, just recognised that I only had 2s and 3s so they must be the values. Half the questions just seemed as though they were there for 'filler' material. Like what was the point in question 2? To see if you knew what a modulus was? Why couldn't they just put it inside another question like an arc-length one where you end up with a modulus and have to choose which sign to use based off restrictions, that is a much better assessment of if someone understands a modulus. Anywho, goodluck on exam 2 everyone!
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Momboom on November 08, 2019, 04:37:43 pm
Likewise. That last question was ridiculous, after the initial implicit diff what even was the point in it? I ended up not even fully simplifying it as there just wasn't enough space, just recognised that I only had 2s and 3s so they must be the values. Half the questions just seemed as though they were there for 'filler' material. Like what was the point in question 2? To see if you knew what a modulus was? Why couldn't they just put it inside another question like an arc-length one where you end up with a modulus and have to choose which sign to use based off restrictions, that is a much better assessment of if someone understands a modulus. Anywho, goodluck on exam 2 everyone!

that wouldn't be much of an assessment either because it was literally the last question of last year's exam 1. no point differentiating between who did last year's paper and who didn't. this paper imo wasn't as bad as what you make it seem to be. yes, none of the questions were insanely challenging like couple of questions last year, but there were a fair share of marks that will be the differentiating factor and that's how exam 1 is usually. exam 2 is usually where the main differentiating happens. good luck
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Jackson.Sprigg on November 08, 2019, 05:08:06 pm
this paper imo wasn't as bad as what you make it seem to be.

HuSh, post exam discussion is always for meaningless venting hehe
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: MubMurshed on November 08, 2019, 06:38:40 pm
Hi,

I have a question about the problem involving the complex number having 0 real part.

I answered with n = 12k +- 3, k is an integer.

A more simple expression would have been n= 3 + 6k, k is an integer.

The question didn’t specify a specific form and both expressions list the exact same values of n. Will this receive full marks because it still finds all integer n values?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Ali Ali on November 08, 2019, 07:08:53 pm
that wouldn't be much of an assessment either because it was literally the last question of last year's exam 1. no point differentiating between who did last year's paper and who didn't. this paper imo wasn't as bad as what you make it seem to be. yes, none of the questions were insanely challenging like couple of questions last year, but there were a fair share of marks that will be the differentiating factor and that's how exam 1 is usually. exam 2 is usually where the main differentiating happens. good luck

Whilst I don't speak for the person above, personally i believe the problem is that the way they've decided to create deciding marks was literally a wall of year 10 algebra that you're gonna need to get through. It doesn't divide the cohort based on how good they are at mathematical concepts, how good their understanding of the material is or anything, but literally just how lucky you are to not screw up a few algebra questions. On a question like the last one, literally anyone could have screwed it up on a bad day, whilst say the last question of the NHT exam required a bit of thinking and recognition and could actually separate those who understood the concepts and those who studied the night before. Overall separation felt like it was very dependent on people making small mistakes, which doesn't really help separate those truly good at specialist math and those who aren't.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: Momboom on November 08, 2019, 09:56:29 pm
but literally just how lucky you are to not screw up a few algebra questions. Overall separation felt like it was very dependent on people making small mistakes, which doesn't really help separate those truly good at specialist math and those who aren't.

but my point is, exam 1's always been like that, both for methods and spesh. (jeez, just look at this year's methods even worse than this paper) last year final question was an exception but if you look at past years VCAA and even 2019 NHT, most questions are just about not making algebra error and good number manipulation skills, that's just exam 1. It's always 35-38 marks of not making careless algebra error, and then 2-5 marks of hard earned marks, and we did have a couple of hard marks this year, just like expected. Algebra separates exam 1, deeper knowledge separates exam 2. It's always been like that, and in that regards VCAA did their expected job so far.
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: ahatzis on November 08, 2019, 10:09:22 pm
The answers assume that the tension forces in 9b are equal to each other but since they are different strings at different angles would they have different tension forces?
Title: Re: VCE Specialist Maths Exam 1 - 08/11/19 - Discussion/Questions/Solutions
Post by: S_R_K on November 08, 2019, 11:15:29 pm
The answers assume that the tension forces in 9b are equal to each other but since they are different strings at different angles would they have different tension forces?

There is only one string, so the tension is constant throughout its entire length. The direction of the string is altered when it passes through a frictionless ring (this is analogous to a pulley system). The different sections of string make different angles with the horizontal due to the force F.