Cos(1,5пи+2x) - cosx=0
Sin2x-sin(π/2-x)=0 2sin(3x/2-π/4)cos(x/2+π/4)=0 sin(3x/2-π/4)=0 3x/2-π/4=πn 3x/2=π/4+πn x=π/6+2πn/3 cos(x/2+π/4)=0 x/2+π/4=π/2+πn x/2=π/4+πn x=π/2+2πn