posted by Anonymous .
Solve the equation cos3x=1^2 where x is radian
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.