Question

use the coterminal angle to find the exact value of the expression: cos 420
how do you do this? please help!

Answer 1

cos 420 will be the same value as cos 60 since we're dealing with a 360 degree circle. cos 60 is 1/2 due to the unit circle.

Answer 2

so would it be 420-360 that equals 60?

Answer 3

Exactly.

Answer 4

thank you!

Answer 5

also, the next part of the question is if coterminal = 60 degreees. then what does cos 420 equal?