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# Maths Integrating trigonometric functions watch

1. 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
2. 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 ?
3. (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?
4. (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
5. (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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