Question

2cos^3x=sin(5пи/2 - x)

Answer 1

2cos^3x=sin(5Π/2-x)
2cos^3x=cosx
2cos^3x-cosx=0 | : на cosx
2cos^2x-1=0
2cos^2x=1
cos^2x=1/2
cosx=+-√2/2
x=-Π/4+2Πn, n€Z
x=Π/4+2Πn, n€Z