Suggested Answers and Discussion - 2016 VCE Methods Exam 1

[decentxion]

Hi, so I really really messed up this exam. Was hoping for full marks or close to that, but got 34 or 35/40. I misread a question and spent a lot of time on that, then ran out of time at the end. I am absolutely devastated and am praying for some encouraging words from somebody?? Is a 40+ still on the cards with low A+ SACs? I have been trying to forget about it all day because I want to go into exam 2 tomorrow with a clear mind, but I am feeling really disheartened.

Really sorry to hear that! People make mistakes sometimes, and it's very common that students choke on their exams, due to all that pressure.

On the bright side, getting a 34-35/40 is still a high A, and so, with your low A+ SAC scores, you might still be able to score a 42+ in the subject given you smash Exam 2!

It's definitely not easy forgetting about things you regret from a day ago, but I encourage you to do your best in forgetting about it! Aim for that high Exam 2 score, give it your all, and walk out of the exam room feeling proud that you've done all you could! I had a similar issue in my Methods exam back in the day, as I made a simple error which made me lose 2 marks in Exam 1! However, I accepted what I got, and aimed to do my best in Exam 2 to make up for it in order to aim for my goal of 45+ in Methods! And I managed to do it!

Wish you all the best in Exam 2. Be very careful in reading the questions, and watch out for the tricks they might use in the questions!

[meddentdream]

Can anyone tell me where I could be looking at for study score??
I'm so devastated, at the start of the year i was doing terribly, with two sacs of B, but then improved drastically as the year went on, getting an A on the last sac and even in my practice exams have been getting A+'s, but today i stuffed up bad, getting a 32-33/40 (i can't remember what i put down for one question)
If i kind of make up for it tomorrow, get a low A+ or high A, what score can i be looking at, if i am ranked mid-high in a very tough cohort?
thank you!

[THEBEAST]

Hey just a few quick questions
 Q1 a) and b)- did u have to specifically define u and v cause i directly showed use of product rule
Q4- i didnt define it as a binomial distribution but rather just write (2/3)^4 for working out, is this fine?

[decentxion]

Okay peeps I got a few questions about some of my answers:
Q3a- how good did our graph have to be in order to get the full 2 marks? I got all the points and the asymptotes but i fear my graph drawing skills aren't exactly perefct (i.e the graph above y=2 wasn't a very good reflection of the graph below it)
Q4c- could we have left it as (16/81)^6 and gotten the mark, or did we have to simplify?
Q5a. iv- I used the second derivative test to determine the nature of the stationary point- d'you reckon they'd count that as valid?
Q5b. i- I stated that because the range of the inverse function was equal to the original's domain, you take the negative- would this be fine?
Q6a- did we have to include the unit per unit?
Q6b- I added 'units' to the end of my answer, because it asked for average value- that's not a problem, right?
Q8a- I antidifferentiated the x^(k-1) equation to get an expression, but then I left it there- could I still get 1 mark?
Q8b. ii-I stated that the median value was found from the integral from 0 to m, where m is the median value, which would equal 0.5. I then got the answer from part b (i) and approximated that using e=2.5, giving me an approximation of 13/25. I then stated that the median value would have to be greater the 1/e due to the area from 1/e to 1 being greater than 0.5. Would this allow me to get the full 2 marks?

Thanks heaps!! 

3a) - VCAA provided you with a grid, so I think they're assuming you're calculating each point to get a close to perfect graph, so that it's to scale. However if you've labelled all the points, and the graph's only worth 2 marks, you might be able to get away with it. Don't quote me on that though.
4c) - In the Study Design, it's been pointed out that VCAA expects all answers to be in the simplest form. Many people put down (16/81)^6, though, since it's a follow-on from part a). Can't confirm you'll get the marks, but likely you will!
5a) - 2nd derivative is not on the Methods Study Design, so it's not accepted as valid working. People in Spesh tend to fall into the trap of taking the easy way out and double diffing.
5b) - That sounds reasonable, but depending on how you word it, it may or may not explain why you actually choose the negative solution. As long as you infer that you're choosing the -ve solution so it fits within the domain of the original (or range of inverse), you should be fine.
6a) - Back in my day I was always told to put units in when they ask for area, rate of change and other things. Not really sure if it matters, but it's a safeguard in case they are harsh and look for units! Highly unlikely to get penalised though.
6b) - No, that's not a problem.
8a) - What do you mean by "you left it there"? The question asked to show using differentiation, not anti-diff though. I'm not sure if that'll pass as valid.
8bii) - That's exactly what I've written in my suggested solutions, except in Maths form! So yes, that's perfect.

Good luck for Exam 2!

[decentxion]

Can anyone tell me where I could be looking at for study score??
I'm so devastated, at the start of the year i was doing terribly, with two sacs of B, but then improved drastically as the year went on, getting an A on the last sac and even in my practice exams have been getting A+'s, but today i stuffed up bad, getting a 32-33/40 (i can't remember what i put down for one question)
If i kind of make up for it tomorrow, get a low A+ or high A, what score can i be looking at, if i am ranked mid-high in a very tough cohort?
thank you!

You would be looking around the 38+ SS range. Good luck for Exam 2!

[decentxion]

Hey just a few quick questions
 Q1 a) and b)- did u have to specifically define u and v cause i directly showed use of product rule
Q4- i didnt define it as a binomial distribution but rather just write (2/3)^4 for working out, is this fine?

Q1) - Depends on what your working looked like. If it shows u and du/dx and v and dv/dx clearly in your dy/dx expression before simplifying it, that should be fine.
Q4 - Yep, that's fine. Doesn't need to be solved via binomial distribution. Same with part c).

[exit]

Q1) - Depends on what your working looked like. If it shows u and du/dx and v and dv/dx clearly in your dy/dx expression before simplifying it, that should be fine.
Q4 - Yep, that's fine. Doesn't need to be solved via binomial distribution. Same with part c).

Hey,thanks for the contribution! Do you think is ok in the last question to find the area from 0 to 1/e is 12/25. (without any inequalities) then say 'therefore the median is greater'. Not sure i will get 2 marks for that since it is 'explain'.

Also for (0,0) a few people questioned me and said its an absolute minimum, not a local minimum. Most people just put 'minimum'. So is 'local minimum' really required?

Additionally, i saw that spesh working is not accepted. Is working from the old study design recommended? (for example, using determinant to solve simultaneous equations)

[decentxion]

Hey,thanks for the contribution! Do you think is ok in the last question to find the area from 0 to 1/e is 12/25. (without any inequalities) then say 'therefore the median is greater'. Not sure i will get 2 marks for that since it is 'explain'.

Also for (0,0) a few people questioned me and said its an absolute minimum, not a local minimum. Most people just put 'minimum'. So is 'local minimum' really required?

Additionally, i saw that spesh working is not accepted. Is working from the old study design recommended? (for example, using determinant to solve simultaneous equations)

Your working for your last question should be fine, as long as you use e>5/2 somewhere in your working.

Technically the turning point was an absolute minimum, but usually when describing the nature of a stationary point in and of itself, you call it a local minimum/maximum. It's just playing safe. You're not wrong in putting minimum or absolute minimum down.

Working from the old study design isn't recommended, no. Try to stick to what you've learnt in the current study design. I was under the impression that the determinant was still in the course and usable? Perhaps not. Still worthwhile to learn about though

[Orb]

5a) - 2nd derivative is not on the Methods Study Design, so it's not accepted as valid working. People in Spesh tend to fall into the trap of taking the easy way out and double diffing.

Even though it's not on the study design any valid Mathematical explanation is accepted. So your 2nd derivative method is perfectly fine

(I personally asked the Chair of the Exam Panel + Chief Assessor so yes this is definitely okay)

[JellyBeanz]

Actually i was going to use the double derivative but was afraid it wouldn't be accepted. Resorted to showing the slops manually.

[decentxion]

Even though it's not on the study design any valid Mathematical explanation is accepted. So your 2nd derivative method is perfectly fine

(I personally asked the Chair of the Exam Panel + Chief Assessor so yes this is definitely okay)

Noted! Thanks for the info

[nishali123]

Hi, I stuffed up all my methods sacs and my sac average ended up being 44 %. If I get 25/40 for exam 1 and 55/80 for exam 2 do I have a chance of getting a study score of 30?
thanks

[Alex.Lindeman]

Hey guys 2 questions...
1. With question 5)IV) If i worked out the stat points correctly and with previous knowledge of the function knew that it was a local min, would i get any marks for not showing how I got the Nature?

2. With 5)b) If i wrote k^-1(x) = -sqrrte^x-1 without stating that I got only the neg answer from the restriction, (only working to show was circling the domain) would i get the marks?

[TimGFranklin]

I messed up question 4a, using (1/3)^4 instead of (2/3)^4 then did the rest of question 4 with pr(none) = (1/81)
If i did the other 2 parts of the questions correctly e.g. pr(X>1) = 1-pr(0) = (80/81) can i receive consequential marks for 4b and 4c?

[SONE0413]

can i still get over 33 SS if i only got like 60% for this exam thx xo (70% avg for SACs