Question

solve each of the equations for 0≤x<2π.
2cos^2 x-1-cosx=0
sin^2 x+cos2x-cosx=0

Answer 1

Pretty sure you can just solve this as a quadratic

Answer 2

1st equation
2cos^2(x)-cos(x)-1=0
(2cos(x)+1)(cos(x)-1)=0
2nd equation
sin^2(x)+cos^2(x)-cos(x)=0
1-cos^2(x)+cos^2(x)-cos(x)=0
1-cos(x)=0
-(cos(x)-1)=0

similar solution
cos(x)-1=0
cos(x)=1
x=cos^-1(1)
x=90 degrees or pi/2