Question

Solve the equation cos3x=1^2 where x is radian

Answer 1

cos 3x = 1

we know cos 0 = 1 and also cos 2π=1
so 3x = 0 or 3x = 2π

x = 0 or x = 2π/3
the period of cos 3x = 2π/3,
so a general solution is

x = 2πk/3, where k is an integer.