This is what my calculator is giving me: $\displaystyle \int {\cos (1 - x)dx = \sin (x - 1)} $ This is obviously wrong. Could anyone explain why it's doing this?
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Hello, Originally Posted by RedBarchetta This is what my calculator is giving me: $\displaystyle \int {\cos (1 - x)dx = \sin (x - 1)} $ This is obviously wrong. Could anyone explain why it's doing this? I'm finding it correct It's just that -sin(x)=sin(-x) and hence the result
It is not wrong. $\displaystyle \int \cos{(1-x)} dx = -\sin{(1-x)} = \sin{(-(1-x))} = \sin{(x-1)}$ Recall that Sine is an odd function: $\displaystyle \sin{(-u)} = -\sin{u}$
I didn't notice the change from (1-x) to (x-1)
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