2017 HSC Mathematics Paper thoughts (1 Viewer)

pikachu975

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Some one please send link to the paper thanks.
NESA doesn't allow posting of their papers as they have copyright I've read on another forum but they post the paper fast, should be there tmrw
 

boredofstudiesuser1

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It was fine tbh. Lost 7 marks defs for the last two qs and the find x for sin a = sin b qs. Hope I get 85+ fml
For the Sina = sinb I'm pretty sure you just had to have them equal each other and then I got something like 3.75m.

Not sure if anyone found an easier way, but for the proof, I said that Sina was O/H for its triangle (did the same for sinb) and then differentiated - and got the result.

Easier way to do it? It was a tedious differentiation for 2 marks.. (if I remembered correctly)
 

xern7777

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What did everyone get for the values of 'a' in the limiting sum = 2 question?? I got 0<a<4 but not sure
This is still subject to review, but apparently a GP with r=0 cannot exist to form a limiting sum of 2, as a=2 for that to occur. Thus your series is 2+0+0+0+0,..... Term2/Term1=0/2=0 but Term3/Term2=0/0=undefined. So a GP must have a non-zero common ration, if 'a' is a non-zero number. Which means the answer may be 0<a<4, a is not equal to 2 (when r=0). Pretty sure this question was designed to trick the state though, so I'm not sure how they'll receive it in the marking center. But it is 3 marks, so other than rearrange the question or graphing/determining the range for 2 marks, the other one is likely gained by recognizing the restriction.

The only case where a zero GP may exist is when 'a'=0 i.e. 0,0,0,0,... which doesn't provide a limiting sum of 2.
 
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The exam was easier in comparison to past years, only question that would have thrown people was limiting sum and geo proof however from what i hear most got at least 1 mark for identifying or making some progress to the solution.
 

Sxerks3

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It wasn't too bad, I'm looking at around 93/94 to 96 raw, depending on how harshly they mark it.
Screwed up the loan repayment, as I put it = 0, instead of 80,000.
Couldn't factorise dL/dx to find x.
Everything else was alright.
 

1729

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This is still subject to review, but apparently a GP with r=0 cannot exist to form a limiting sum of 2, as a=2 for that to occur. Thus your series is 2+0+0+0+0,..... Term2/Term1=0/2=0 but Term3/Term2=0/0=undefined. So a GP must have a non-zero common ration, if 'a' is a non-zero number. Which means the answer may be 0<a<4, a is not equal to 2 (when r=0). Pretty sure this question was designed to trick the state though, so I'm not sure how they'll receive it in the marking center. But it is 3 marks, so other than rearrange the question or graphing/determining the range for 2 marks, the other one is likely gained by recognizing the restriction.

The only case where a zero GP may exist is when 'a'=0 i.e. 0,0,0,0,... which doesn't provide a limiting sum of 2.
?
 

PARLIAMO314159

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I'm also wondering this.
Yep, as the mathematics you used to attain either answer is correct, as you rounded to 2 sig figs, and they didn't specify to use the rounded value of k in part iii, i.e., through using the directive 'hence', etc. Essentially, if the method's correct, they'll accept the solution, especially considering that sizeable proportion of the 2017 2u/3u cohort would've answered part iii using the rounded figure.
 

1729

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This is still subject to review, but apparently a GP with r=0 cannot exist to form a limiting sum of 2, as a=2 for that to occur. Thus your series is 2+0+0+0+0,..... Term2/Term1=0/2=0 but Term3/Term2=0/0=undefined. So a GP must have a non-zero common ration, if 'a' is a non-zero number. Which means the answer may be 0<a<4, a is not equal to 2 (when r=0). Pretty sure this question was designed to trick the state though, so I'm not sure how they'll receive it in the marking center. But it is 3 marks, so other than rearrange the question or graphing/determining the range for 2 marks, the other one is likely gained by recognizing the restriction.

The only case where a zero GP may exist is when 'a'=0 i.e. 0,0,0,0,... which doesn't provide a limiting sum of 2.
The syllabus only places restriction |r| < 1 for limiting sum
 

shehan123

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The syllabus only places restriction |r| < 1 for limiting sum
This is true, we never go over the case of R=0, but then the man spits a good point, 3 marks for that 0 < a < 4 seems a little dodgy.
 

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