Question

$\int _0^{\pi }\sin \left(x\right)dx$

solve

Answer 1

$\int _0^{\pi }\sin \left(x\right)dx=2$

$\mathrm{Use\:the\:common\:integral}:\quad \int \sin \left(x\right)dx=-\cos \left(x\right)$

$=\left[-\cos \left(x\right)\right]^{\pi }_0$

$\mathrm{Compute\:the\:boundaries}:\quad \left[-\cos \left(x\right)\right]^{\pi }_0=2$

= 2