Question

What is x in this equation?

Answer 1

\[\cos^2x +3cosx+2 = 0\]

Answer 2

u = cosx

Answer 3

Oh then its just a quadratic :O

Answer 4

:P What happens to the cos though? Do it after?

Answer 5

u^2 + 3u + 2 = 0
solve for u then later sub it back in

btw is it only me that latex is not working?

Answer 6

Okay, thank you. I think its just you:O

Answer 7

np

Answer 8

I can't believe I didn't see it was just a simple quadratic *.*

Answer 9

well using a substitution is easier; at times when you see like the x squared; there is a high chance that its a quadratic. so use a substitution.

Answer 10

Alright! Thank you so much:D