Question

what is the value of 5^3i^9?
A.–125i
B.–15i
C.15i
D.125i

Answer 1

\[\huge 5^{3\cdot i^9}\]\[\large i^9 = i^{2+2+2+2}+i^1\implies \color{red}{(i^2)(i^2)(i^2)(i^2)}+i^1\]\[\large \color{red}{i^2 =-1}\]\[\large 5^3 = 125\]You can go on from here.

Answer 2

Thanks!

Answer 3

No problem :)