Question

What is `cos^-1(cos(4pi)/5)`?

Answer 1

`cos^-1(cos(4pi)/5)=78.463^o`

Explanation:

As `cos(4pi)=1`,

`cos(4pi)/5=1/5=0.2`

and from calculators we get `cos^-1(0.20)=78.463^o`