The solutions for cos^2 x - cos 2x =0, over the domain 0 < x < 2π are

a. π/6 & 5π/6

b. π/2 & 3π/2

c. 0 & π & 2π

d. π/4 & 3π/4 & 5π/4 & 7π/4

*need to know steps*




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