Question

How do I apply the double angle formula to cos(450)?

Answer 1

\[\cos 450 = \cos (360 + 90)= \cos 90\]
Why do you need to use double angle formula?

Answer 2

The question is asking me to find the exact value using the ouble angle formula. I did reduce to cos90 and did cos180=2cos^2(90)-1. But apparently i was wrong

Answer 3

it was cos(90)

Answer 4

So even applying double angle formula you get the same result?

Answer 5

yes

Answer 6

Ok so I'll skip that process next time thank you.

Answer 7

welcome :)