2009 Mathematics 2U HSC Worked Solutions (1 Viewer)

T.Goodhew

Actuarial Co-op 06
Joined
Oct 31, 2006
Messages
31
Gender
Male
HSC
2005
Hi everyone,

Please find "sample solutions" to the 2009 Mathematics (2 Unit) HSC Exam at 2009mathsHSCsoln_v1.2.pdf. (Updated Solutions, all errors fixed)

I realise there is another thread offering solutions however that only shows the final answers.

Before viewing the solutions please understand:

  • The solutions are not endorsed in any way by NSW Board of Studies
  • These are only "sample solutions" there may be more than one way to correctly answer a question
If you do find any errors in the solutions, please post them here.

Cheers and Good Luck with the rest of your exams :)
Tim
 
Last edited:

Scinery

Member
Joined
Dec 15, 2007
Messages
279
Gender
Male
HSC
2009
oh fml that was a depressing read

should not have read that :(
 

boxhunter91

Member
Joined
Nov 16, 2007
Messages
736
Gender
Male
HSC
2009
He missed out that drawing question on q8..
Looks like i done preety well.
 

Thecorey0

Member
Joined
Oct 28, 2008
Messages
428
Location
Goldstein
Gender
Male
HSC
2009
Thanks dude. Q5cii2 seems to be wrong. The triangle is an equilaterial, and hence all sides are 2. In your working you have forgot the '2' in the -2absinc bit. The answer should be 2 + 2pi/3. It's good to know my answers are right. I can now say confidently that I got 114-115.
 

tku336

Member
Joined
Apr 8, 2009
Messages
248
Gender
Male
HSC
2009
Fuck. I wrote the answers down on my sheet, so now I know exactly how many stupid mistakes I made. 110-112, with 6 marks worth of stupid errors.

P.S. Can somebody explain why 9a) everybody multiplied the chances? Surely multiplication means AND, nor OR. You should have added 8/9 + 15/16, cubed that, then 1- that., surely.
 

Thecorey0

Member
Joined
Oct 28, 2008
Messages
428
Location
Goldstein
Gender
Male
HSC
2009
Fuck. I wrote the answers down on my sheet, so now I know exactly how many stupid mistakes I made. 110-112, with 6 marks worth of stupid errors.

P.S. Can somebody explain why 9a) everybody multiplied the chances? Surely multiplication means AND, nor OR. You should have added 8/9 + 15/16, cubed that, then 1- that., surely.
Well the odds that neither of them win in any given week = 8/9*15/16 =5/6. Hence the odds that they don't win for 3 continious weeks - i.e. don't win at all = (5/6)^3. Therfore the odds of winning at least once is 1 - (5/6)^3 = 91/216.
 

tku336

Member
Joined
Apr 8, 2009
Messages
248
Gender
Male
HSC
2009
Eh. I'll get 1/2 for that anyway. Do you know what a 110-112 would align to?
 
Joined
Sep 9, 2008
Messages
247
Gender
Female
HSC
2009
hmmm..i think i did better than i thought....nowhere near you guys but around 80 i think
 
Joined
Sep 26, 2008
Messages
1,948
Gender
Female
HSC
2009
im not going to read that. ill end up comitting suicide if i do LOL.

bye sydney uni, nice dreaming of you :(
 

absorber

Member
Joined
Apr 10, 2009
Messages
874
Gender
Male
HSC
2009
I think your answer with the savings question is wrong, I got something like $129966 as opposed to your $128k; and I'm not alone.

Is it because you rounded up the payments to 179? he didn't need a full payment the last time, like .4 of a payment or something, hence shouldn't be regarded as a full payment
 

T.Goodhew

Actuarial Co-op 06
Joined
Oct 31, 2006
Messages
31
Gender
Male
HSC
2005
Thanks dude. Q5cii2 seems to be wrong. The triangle is an equilaterial, and hence all sides are 2. In your working you have forgot the '2' in the -2absinc bit. The answer should be 2 + 2pi/3. It's good to know my answers are right. I can now say confidently that I got 114-115.
Absolutely correct, thanks for pointing that out! :D

*Solutions updated*
 
Last edited:

T.Goodhew

Actuarial Co-op 06
Joined
Oct 31, 2006
Messages
31
Gender
Male
HSC
2005
I think your answer with the savings question is wrong, I got something like $129966 as opposed to your $128k; and I'm not alone.

Is it because you rounded up the payments to 179? he didn't need a full payment the last time, like .4 of a payment or something, hence shouldn't be regarded as a full payment
This is also correct, although the answer will vary between $129965 and $129966 depending on where you have rounded in your working. At first glance, I had thought a broad brush calculation would suffice but in hindsight you are absolutely correct and the fractional monthly repayment should have been dealt with correctly.

*Solutions updated*
 
B

babypunk313

Guest
hey, im only lookin at gettin about 90ish but in Q7,a,ii:
(u+1)(4u-1) would make 4u^2+3u-1, wouldnt it? you're meant to get 4u^2+3u+1.
i tried to do it in the test but i couldnt get past that :(
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top