Suggested Answers to the HSC 2016 Mathematics Exam (+Discussion!)

[browny2409]

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

[jamonwindeyer]

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! I think what is there has implemented all the corrections I've received, let me know if you spot more now

[Klexos]

Sigh, these solutions are stressing me out - I'm going to just settle for that mid band 5 goal LOL

[jamonwindeyer]

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

[ml125]

Pretty sure 15ciii should be h=y/x

[itsAnuu]

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

[pikachu975]

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

[lha]

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?

[zachary99]

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)       

[jamonwindeyer]

Pretty sure 15ciii should be h=y/x(Image removed from quote.)

Woops! I'd already fixed that, image didn't change, should work now could you confirm?

[jamonwindeyer]

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

[jamonwindeyer]

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)

[ml125]

Woops! I'd already fixed that, image didn't change, should work now could you confirm?

Yep, works now haha

[itsAnuu]

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

[jamonwindeyer]

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!

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)