Carrotsticks' Solutions 2015 Extension 2 HSC (1 Viewer)

Mathsisfun15

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Now my careless errors will haunt me forever. How I screwed up the product rule I will never know
 

Physicklad

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hey carrot how many marks would i lose for saying the product of the coses in the second last question was (-1)^n
 

Drsoccerball

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Carrot what do program do you use to type up your exams and solutions?
 

Carrotsticks

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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

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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

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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

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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

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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

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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.
 

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