1. 4cos^2 3x = 1

2. cos(2x-pi/2)=root2/2

3. cos2x=sinx+1

4. sin6xcosx-cos6xsinx= - root3/2

4. cos2x-4=3cosx-4sin^2x

Please explain to me how to solve these!!

Also, how can i type the root or squares out like I see people do in this forum? or is it an image?