Carrotsticks' Solutions 2015 Extension 2 HSC (1 Viewer)

Mathsisfun15

Active Member
Joined
Apr 25, 2015
Messages
157
Gender
Male
HSC
2015
Now my careless errors will haunt me forever. How I screwed up the product rule I will never know
 

Physicklad

Member
Joined
Aug 8, 2015
Messages
60
Gender
Male
HSC
2015
hey carrot how many marks would i lose for saying the product of the coses in the second last question was (-1)^n
 

Drsoccerball

Well-Known Member
Joined
May 28, 2014
Messages
3,650
Gender
Undisclosed
HSC
2015
Carrot what do program do you use to type up your exams and solutions?
 

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
hey carrot how many marks would i lose for saying the product of the coses in the second last question was (-1)^n
If that is all you just said, with nothing else, then most likely zero.

The mark allocation I am guessing for that Q is

1 for finding the roots

1 for using product of roots and acquiring the correct answer (not necessarily closed form)

1 for finding the closed form for the binomial series

That last mark may or may not be there, it could perhaps be allocated towards simply identifying that the product of roots was relevant to the question.

Now my careless errors will haunt me forever. How I screwed up the product rule I will never know
If it makes you feel better, I stuffed that one up too when doing the solutions. Only realised it was wrong when my result was useless for the next part.

Carrot what do program do you use to type up your exams and solutions?
Math Type and Microsoft Word. Diagrams also done using Microsoft Word.
 

Physicklad

Member
Joined
Aug 8, 2015
Messages
60
Gender
Male
HSC
2015
If that is all you just said, with nothing else, then most likely zero.

The mark allocation I am guessing for that Q is

1 for finding the roots

1 for using product of roots and acquiring the correct answer (not necessarily closed form)

1 for finding the closed form for the binomial
that wasnt all i said - i worked out the roots and wrote the formula for product of roots but i used the leading coefficient as one instead of the sum of binomial coefficients
 

JACO

New Member
Joined
Oct 18, 2014
Messages
7
Gender
Undisclosed
HSC
2016
That's exactly what I did, then used trial and error to try and see if I was right, but then when I subbed n = 1, the product came to -1/2, then tried with n = 2, and the product came to 1/8, then when n = 4, the product was =-1/32 ... so I knew the denominator was increasing by odd powers of 2, which is 2^(2n-1), so I just put (-1)^n / 2^(2n-1) as my final answer, without evaluating the sum of the binomials. Hopefully 2/3 marks.
 

4025808

Well-Known Member
Joined
Apr 2, 2009
Messages
4,377
Location
中國農村稻農
Gender
Male
HSC
2011
Uni Grad
2017
Holy shit the probability was fucked, gg for that one. Did not see that one coming. But apart from that the rest of the paper didn't seem too difficult tbh.
 

RealiseNothing

what is that?It is Cowpea
Joined
Jul 10, 2011
Messages
4,591
Location
Sydney
Gender
Male
HSC
2013
that wasnt all i said - i worked out the roots and wrote the formula for product of roots but i used the leading coefficient as one instead of the sum of binomial coefficients
Probably only 1/3 if you got (-1)^n but you never know.
 

sida1049

Well-Known Member
Joined
Jun 18, 2013
Messages
926
Gender
Male
HSC
2015
Holy shit the probability was fucked, gg for that one. Did not see that one coming. But apart from that the rest of the paper didn't seem too difficult tbh.
Yep - that pretty much sums up my experience of the exam.
 

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

Top