Please give step by step and explain to get A+ rating Solution int f(x) dx (x from 0 to ) = 1 Thus int k.e-x/2 dx (x from 0 to ) = 1 -2k.e-x/2 (x from 0 to ) = 1 -2ke- - (-2ke0) = 1 0 + 2k = 1 k = 1/2 P(X >= 1) = int f(x) dx (x from 1 to ) = int 1/2 e-x/2 dx (x from 1 to ) = -e-x/2 (x from 1 to ) = -e- - (-e-1/2) = 0 + e-1/2 = e-1/2.