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# GCSE 9-1 paper mark scheme is wrong? watch

1. http://qualifications.pearson.com/co...s-2015-SAM.pdf

So I'm doing the second paper higher tier, (second last paper on that pdf)

Page 137 of pdf, question 19 of paper 2 higher.

Question b is a transformation question, I applied the transformation but the mark scheme says the wrong y value.

The point (-2,0) applied to the transformation -f(x) + 3 is surely (-2, 3) I don't see it any other way but the mark scheme says (-2,2)?

Also question 21 a on the same paper.

I'm using basic sine rule ratios to work out the missing side, then use the area of the triangle rule half ab sine C to get an area of 22.6 correct to 3sf, however mark scheme says 130. Can anyone help? I don't see how they got 130.

and the second part I'm pretty sure its talking about the ambiguous case of sine rule of obtuse and acute angles.

However for the ambiguous case to take effect, they have to be talking about angle PQR, which the question says we assume to be acute.

Mark scheme says PRQ obtuse, but that can't be right because the question states PRQ is 32, and the ambigious case will only work if PQR is the acute/obtuse one.

Cheers guys.
2. (Original post by Geko_Student)
http://qualifications.pearson.com/co...s-2015-SAM.pdf

So I'm doing the second paper higher tier, (second last paper on that pdf)

Page 137 of pdf, question 19 of paper 2 higher.

Question b is a transformation question, I applied the transformation but the mark scheme says the wrong y value.

The point (-2,0) applied to the transformation -f(x) + 3 is surely (-2, 3) I don't see it any other way but the mark scheme says (-2,2)?
Yes there is a mistake in the mark scheme.

It would be a good exercise for you if you work out using the original graph what is. Then apply the transformation algebraically and verify that (-2, 2) does not lie on this transformed graph.

I'll help with the other question later when I have time, if it hasn't been answered already. Tag/quote me if I forget.
3. (Original post by notnek)
Yes there is a mistake in the mark scheme.

It would be a good exercise for you if you work out using the original graph what is. Then apply the transformation algebraically and verify that (-2, 2) does not lie on this transformed graph.

I'll help with the other question later when I have time, if it hasn't been answered already. Tag/quote me if I forget.
Ok don't know why or how the mark scheme can be wrong.

Did you check the triangle question as well?

http://i.imgur.com/JYQjkg3.png

I simply don't understand how they got 130 as the answer?

I make it 22.6 (3sf), and even in the ambiguous case the 130 doesn't add up.
4. (Original post by Geko_Student)
Ok don't know why or how the mark scheme can be wrong.

Did you check the triangle question as well?

http://i.imgur.com/JYQjkg3.png

I simply don't understand how they got 130 as the answer?

I make it 22.6 (3sf), and even in the ambiguous case the 130 doesn't add up.
That's another mistake in the mark scheme. They've given the answer as 22.5-22.6 in the notes and then randomly put 130 as the answer.

This is only a specimen paper so they won't have checked it as thoroughly as a real paper. But it is surprising that there are two mistakes.

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