Evaluate the sum:
\(\frac{1}{2^1} + \frac{2}{2^2} + \frac{3}{2^3} + \cdots + \frac{k}{2^k} + \cdots \)
sumfor(n, 1, 1000, (n/2^n))=It converges to 2
Partial sum formula =2^(-k) * (-k + 2^(k+1) - 2)
+28 
