Question

find the product of (cos 4 pi / 5 + i sin 4 pi / 5) 3 ( cos pi / 6 + i sin pi /6)

Answer 1

This is easier to work with if you convert to exponentials.\[\Large\rm \cos\frac{4\pi}{5}+\mathcal i \sin\frac{4\pi}{5}=e^{4\mathcal i \pi/5}\]What is the 3 in the middle?
Is that supposed to be an exponent?