Question

Решите уравнение cos(2x)=sin(6x)

Answer 1

cos 2x=sin (π/2-2x)
sin (π/2-2x) =sin6x

либо π/2-2x=6x+2πn  8x=π/2- 2πn   x=π/16-π/4 n    n∈Z

либо π/2-2x+6x=π+2πm      9/2x=π+2πm      x=2/9π+4/9πm   m∈Z

Answer 2

Но cos(2*(2/9π+4/9π)) не равен sin (6*(2/9π+4/9π))