sin2α*sin3α-cos2α*cos3α-cos5α = -cos 5a - cos 5a = -2cos 5a
cos(a + b) = cos a * cos b - sin a * sin b
sin2α*sin3α-cos2α*cos3α = - cos 5a
sin2α*sin3α-cos2α*cos3α-cos5α = -cos 5a - cos 5a = -2cos 5a
cos(a + b) = cos a * cos b - sin a * sin b
sin2α*sin3α-cos2α*cos3α = - cos 5a