Question

cos^3x-cosx= 0 решить уравнение

Answer 1

$cos^3{x} - cos{x} = 0\ t = cos{x}\ t^3 - t = 0\ t(t^2-1)=0\ t_1=0\\ t^2-1=0\ t^2=1\ t_2=-1\ t_3=1\\ cos{x_1} = 0\ cos{x_2} = -1\ cos{x_3} = 1\ x_1=frac{pi}{2} + pi*n, n in z\ x_2=2pi*n, n in z\ x_3=pi+2pi*n, n in z$