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# implicit differentiation watch

1. (Original post by Alen.m)
well i know all of that but if you move (cos x- sin y dy/dx) to the other side, which sign will be changed like will it become -(cos x-sin y dy/dx)?
I've attached my workings.

I think what's happened is you've confused your negative and positive signs. I would rewrite anything that looks like cosx-siny to -cosxsiny as it makes it clearer when doing the rest of your workings

You can do this because you know that multiplying a positive by a negative will give a negative answer.
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2. (Original post by Excuse Me!)
I've attached my workings.

I think what's happened is you've confused your negative and positive signs. I would rewrite anything that looks like cosx-siny to -cosxsiny as it makes it clearer when doing the rest of your workings

You can do this because you know that multiplying a positive by a negative will give a negative answer.
yeah that's exactly what my problem was but thanks for your working made it clear but don't you think cos y cos x should be positive before rearranging process starts?
3. (Original post by Alen.m)
yeah that's exactly what my problem was but thanks for your working made it clear but don't you think cos y cos x should be positive before rearranging process starts?
cosycosx comes from differentiating the product run cosysinx so yeah you're right.

I got equally muddled with my signs trying to write on small bits of paper but glad it makes sense
4. (Original post by Excuse Me!)
cosycosx comes from differentiating the product run cosysinx so yeah you're right.

I got equally muddled with my signs trying to write on small bits of paper but glad it makes sense
Yeah mate quite clear thanks
5. (Original post by Alen.m)
AQA page 86 question 10 part b
what year ?
6. (Original post by Student1408)
what year ?
It's a textbook question, not a past paper question.

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