$$ \int_0^2\left|x^2+2 x-3\right| d x \text { is equal to } $$

$$\int\limits_{ - {\pi \over 2}}^{{\pi \over 2}} {\cos x\,dx} $$

$$\int_{ - \pi /2}^{\pi /2} {\sin xdx} $$

The value of the integral $$\int\limits_0^{\pi /2} {({{\sin }^{100}}x - {{\cos }^{100}}x)dx} $$ is