Question

find all values of x in the interval[0,2pie] that satisfies the equation 2+cos2x=3cosx

Answer 1

Is this problem:

2 + cos(2x) = 3 cosx

or

2 + cos ² x = 3 cosx ?

Answer 2

its the first one :)

Answer 3

2 + cos(2x) = 3 cos x

Answer 4

Do you know the double angle formula for cosine?

Answer 5

@xyz10 ---> I'm here to help. Are you still here?

Answer 6

am i going to replace cos 2x with 2 cos^2x-1 ?

Answer 7

I think we will but let's just start.

2 + cos(2x) = 3 cos x

2 + cos² x - sin²x = 3 cos x

Answer 8

We need to get this equation to one variable.

Answer 9

2 + cos² x - ( 1 - cos² x) = 3 cox x

Agree? Question?

Answer 10

yes i agree got it :) thanks a lot

Answer 11

Do you want me to stop now or shall we solve the equation? It's your call.

Answer 12

no thank you so much i think i got it from here . thank you :)

Answer 13

okay

Answer 14

really appreciate your help