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    I've got sin(-x)+cos(-x) dx

    I thought this would integrate to -cos(-x)-sin(-x)

    but the answer first turns it into -sinx+cosx and I have no idea where the '+cosx' comes from - where the minus sign gone?

    And then they integrate to cosx+sinx. Could someone explain the first step the markscheme took? Thanks
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    they want you to recognise that cos(-x) is the same as cos(x)....

    and sin(-x) is the same as -sin(x)

    it is all about the odd & even yeah ?
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    (Original post by the bear)
    they want you to recognise that cos(-x) is the same as cos(x)....

    and sin(-x) is the same as -sin(x)

    it is all about the odd & even yeah ?
    Yeah I didn't recognise that, and what do you mean by the last statement?
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    (Original post by MrToodles4)
    Yeah I didn't recognise that, and what do you mean by the last statement?
    sin(x) is an ODD function

    cos(x) is an EVEN function

    https://www.mathsisfun.com/algebra/f...-odd-even.html
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    (Original post by the bear)
    sin(x) is an ODD function

    cos(x) is an EVEN function

    https://www.mathsisfun.com/algebra/f...-odd-even.html
    Thanks
 
 
 
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