$$\int_0^{{\pi \over 2}} {\left| {\sin x - \cos x} \right|} \,dx$$ is equal to

$$\int_0^{{\pi \over 2}} {{e^{\sin x}}} \cos x\,xdx$$ is equal to

Let $p=\int_a^b f(x) d x$ and $q=\int_a^b|f(x)| d x$. If $f(x)=e^{-x}$, then which one of the following is correct ?