Answer
$[2cis(\frac{5\pi}{9})]^2$
= $-3.7588 - 1.3681i$ (Using calculator and corr. to 4 decimal places)
Work Step by Step
$[2cis(\frac{5\pi}{9})]^2$
= $2^2 cis(\frac{5\pi}{9}) cis(\frac{5\pi}{9})$
= $4 cis(\frac{5\pi}{9} + \frac{5\pi}{9})$ (Product Theorem)
= $4 cis(\frac{10\pi}{9})$
= $-3.7588 - 1.3681i$ (Using calculator and corr. to 4 decimal places)
