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    (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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    (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?
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    (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
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    (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
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    (Original post by Alen.m)
    AQA page 86 question 10 part b
    what year ?
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    (Original post by Student1408)
    what year ?
    It's a textbook question, not a past paper question.
 
 
 
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