(sin2a / (sin2a + cos a)^2) - 1(sin2a / sin^2 a + 2sin a cos a + cos^2 a) - 1(sin2a / 1 + 2sin a cos a + 1) - 1sin2a / (2sin a cos a + 2)sin2a / 2sin a (cos a + 1)sin a / 2(cos a + 1)
(sin2a / (sin2a + cos a)^2) - 1
(sin2a / sin^2 a + 2sin a cos a + cos^2 a) - 1
(sin2a / 1 + 2sin a cos a + 1) - 1
sin2a / (2sin a cos a + 2)
sin2a / 2sin a (cos a + 1)
sin a / 2(cos a + 1)