Question

I have no idea how to do this will you help me please

Answer 1

Using the following property

$a^{bc}=(a^b)^c$

We can rewrite our expression as

$i^{86}=i^{2\times43}=(i^2)^{43}$

i is the imaginary number, also know as the square root of - 1. When squared, the imaginary number is equal to - 1.

$(i^2)^{43}=(-1)^{43}$