Let XXX have PDF f(x)=2e−2xf(x) = 2e^{-2x}f(x)=2e−2x for x≥0x \geq 0x≥0. What is E[X]E[X]E[X]?
0.250.250.25
0.500.500.50
1.01.01.0
2.02.02.0