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26Integral of sin⁡x\sin x from 00 to π\pi

Evaluate ∫0πsin⁡x dx\displaystyle \int_0^{\pi} \sin x\,dx.

Find an antiderivative of sin x, which is −cos x, then apply the fundamental theorem: evaluate it at π and subtract its value at 0. That gives (−cos π) − (−cos 0) = 1 − (−1) = 2.

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