# How did he solve this integral?

## i don't understand how $\left(\sin \left(t\right) + \left\mid \sin \right\mid \left(t\right)\right) = \left(\sin \left(t\right) - \sin \left(t\right)\right)$

$\sin t + \left\mid \sin t \right\mid = 0$ for $t \in \left[\pi , 2 \pi\right]$