sin2x=cos3x<=>cos(90-2x)=cos3x<=>90-2x=+-3x+360*k k apartin lui N <=>-2x+-3x=-90+360*k de unde x=-90+360*k sau x=(-90+360*k)/(-5)<=>x=18+72*k=> x apartine {-90+360*k sau 18+72*k}
