Question

Can someone explain how (cis7pi/12)^6 results in cis(-pi/2) please? (picture attached)

Answer 1

multiply the angle by 6
that is all

Answer 2

i.e. it is easy, not hard
that is why you write a complex number in trig form, makes it easy to do this

Answer 3

I get cis (7pi/2)?

Answer 4

ok

Answer 5

pretty clear that \(\frac{7\pi}{2}\) is conterminal with \(-\frac{\pi}{2}\) right?

Answer 6

yep! OH right coterminal angles.. haha i forgot about that. thank you!!

Answer 7

yw