sin^4a + cos^4a sin2a= (sin^2a)^2 + (1-sin^2a)^2 sin2a= (sin^2a)^2 + (1 - 2sin^2a + sin^4a) sin2a= sin^4a + sin^2a - 2sin^4a sin2a + sin^6a= sin^6a + sin^4a + sin^2a - 2sin^4a sin2a
Таким образом, sin^4a + cos^4a sin2a = sin^6a + sin^4a + sin^2a - 2sin^4a sin2a.
sin^4a + cos^4a sin2a
= (sin^2a)^2 + (1-sin^2a)^2 sin2a
= (sin^2a)^2 + (1 - 2sin^2a + sin^4a) sin2a
= sin^4a + sin^2a - 2sin^4a sin2a + sin^6a
= sin^6a + sin^4a + sin^2a - 2sin^4a sin2a
Таким образом, sin^4a + cos^4a sin2a = sin^6a + sin^4a + sin^2a - 2sin^4a sin2a.