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## Homework Statement

Let alpha = e ^ i8pi / 11 , then find Re ( alpha + alpha ^2 + alpha ^3 + alpha ^4 + alpha ^5).

## Homework Equations

## The Attempt at a Solution

look i hav reduced the expression to [tex]\alpha[/tex] ([tex]\alpha^5[/tex] -1 ) / [tex]\alpha[/tex]-1

now what to do??