Integration of sinx

[polar orchid]

Hi all. Can anyone explain why, when integrating sin(pi/6 - x) results in positive cosx term?
I had thought the integration of the sinx function would result in -cosx.

[earnest thistle]

use u sub

$u=\frac{\pi}{6}-x$

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ImOakley

[earnest thistle]

differentiating gives $\frac{du}{dx}=-1$

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ImOakley

[earnest thistle]

so $dx=-du$

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ImOakley

[earnest thistle]

then you have the integral $\int-\sin{u}du$

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ImOakley

[earnest thistle]

its mutliplied by -1

[polar orchid]

I see.Thanks!

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