Question

find the exact value of cos(-pi) I need help

Answer 1

\(\large\color{slate}{ \cos(-a)=\cos(a) }\) I would think.
.....
and you know \(\large\color{slate}{ \cos(\pi) }\) (or not?_

Answer 2

no

Answer 3

Have you studied the unit circle yet?

Answer 4

yes

Answer 5

you know that \((\cos(x))\) refers to \(x\) values, whereas \((\sin(x))\) refers to \(y\) values?

Answer 6

what about trig func