Question

Find all solutions to the equation in the interval [0, 2π).

cos 2x - cos x = 0

Answer 1

um i haven't done this in a while, but i could try to find an identity for cos2x that is simpler to work with

Answer 2

You probably want to use some trig identities.

Answer 3

Is it cos squared or cos double x?

Answer 4

cos double x

Answer 5

Do you know the double angle formula?

Answer 6

no

Answer 7

look it up.

Answer 8

\[
\cos(2x) =\cos^2(x)-\sin^2(x)
\]

Answer 9

how would i apply that to this problem?

Answer 10

I'm thinking you want to get rid of the double angle because it makes things tougher.