Average value $\quad$ A retarding force, symbolized by the dashpot in the accompanying figure, slows the motion of the weighted spring so that the mass's position at time $t$ is
$$y=2 e^{-t} \cos t, \quad t \geq 0$$
Find the average value of $y$ over the interval $0 \leq t \leq 2 \pi$
(FIGURE CAN'T COPY)