평균값은 \dfrac{1}{\dfrac{\pi}{2}-\bigg(-\dfrac{\pi}{2}\bigg)}\displaystyle\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}2\cos xdx=\dfrac{1}{\pi}\displaystyle\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}2\cos xdx=\dfrac{2}{\pi}\bigg[\sin x\bigg]_{-\frac{\pi}{2}}^{\frac{\pi}{2}}

= \dfrac{2}{\pi} (\sin(\dfrac{\pi}{2}) - \sin(-\dfrac{\pi}{2}))=\dfrac{2}{\pi}(1-(-1))=\dfrac{4}{\pi}이다.