Answer
The sum = $\frac{7}{81}$
Work Step by Step
Given i = 2 to 4
Then the sum = $(-\frac{1}{3})^{2}$ + $(-\frac{1}{3})^{3}$ + $(-\frac{1}{3})^{4}$
= $(\frac{1}{9})$ + $(-\frac{1}{27})$ + $(\frac{1}{81})$
= $\frac{(9-3+1)}{81}$
= $\frac{7}{81}$
