A discrete random variable has P(X=k)=12k+1P(X=k) = \frac{1}{2^{k+1}}P(X=k)=2k+11 for k=0,1,2,…k=0,1,2,\ldotsk=0,1,2,…. What is E[X]E[X]E[X]?
0.5
1
1.5
2