What is the average value of f(x)=e−xf(x) = e^{-x}f(x)=e−x on [0,2][0, 2][0,2]?
(1−e−2)/2(1-e^{-2})/2(1−e−2)/2
(e−2−1)/2(e^{-2}-1)/2(e−2−1)/2
1−e−21-e^{-2}1−e−2
e−2e^{-2}e−2