Question

NEED HELP! DON'T UNDERSTAND! (The is supposed to be a Greek E)
10
E 2^i
i=1

A. 2046
B. 2047
C. 1024
D. 2048
E. 1023

Answer 1

try a

Answer 2

Can you explain how to do it?

Answer 3

You can make use of this formula:
\[\Large\sum_{i=0}^{n-1}ar^i=a\left( \frac{1-r^n}{1-r}\right) \]

Answer 4

\[ \Large \sum_{i=1}^{10}2^i=\sum_{i=0}^{9}2^{i+1}=\sum_{i=0}^92(2^i)\]
so \(a = 2, r=2, n=10\)
n = 10 since 9 = n -1 => n = 9+1 = 10