Homework 16: Convolution

1. Section 3.9, #1.
2. Suppose that \(X\) and \(Y\) are independent random variables with \(f_X(x)=xe^{-x}\), \(x\geq 0\), and \(f_Y(y)=e^{-y}\), \(y\geq 0\). Find the pdf of \(X+Y\).