<PRE><B>Question 310844</B>
Treat it as a regular quadratic equation but in trig form.

2cos^2x = 4cosx - 2

Bring everything to the left side and then equate to zero.

2cos^2x - 4cosx + 2 = 0

Apply the rules for solving a quadratic equation to find cosx.

Can you finish now?

============================================================

I got your reply.  Did you get my reply to this question?  
I simply substituted u for cosx to make the factoring using the quadratic formula a lot easier.  I found the answer for u to be 1.  Then replacing u with cosx, I set cosx = 1.  I know that 0 degrees and 2pi radians (which is the same thing as 360 degrees) is the only solution to your trig equation in quadratic form.

Understand?

</PRE>