Question

2cos suare theta-3cos theta +1=0​

Answer 1

2cos^2x-3cosx+1=0

or,2y^2-3y+1=0(saycosa=y)

or,2y^2-2y-y+1=0

or,2y(y-1)-1(y-1)=0

or,(2y-1)(y-1)=0

y=1/2

or,cosa=1/2

or,a=30

y=1

cosa=1=cos0

a=0