Find the indicated sum.

Question

n
‡”4(0.5)^K
K=1
Help me because I do not know how to solve it.

Answer 1

1/2 + 1/4 + ... + 1/2^n = (2^n - 1)/2^n
or, 1 - 1/2^n

just take 4 times that. Recall that 4 = 2^2