How do you find all solutions of the equations ${cos}^{3} x = cos x$ $cos^3x=cosx$ in the interval $[0, 2 π)$ $[0,2pi)$ ?

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Answer 1 · 2017-01-31T11:57:05

$x = k/2pi, k = 0, +-1, +-2, +-3, ...$ .

$cosx (cos^2x-1)=0$ , cos x =0 and +-1#

Easily, $x = k/2pi, k = 0, +-1, +-2, +-3, ...$ .

How do you find all solutions of the equations cos^3x=cosxcos3x=cosxcos^3x=cosx in the interval [0,2pi)[0,2π)[0,2pi)?