Q2)
sin4xa + cos4xb = 1a+b
bsin4x + acos4x = aba+b
bsin4x + a(1 - sin2x)2 = aba+b
(a+b)2sin4x - 2a(a+b)sin2x + a2 = 0
this is quadratic in sin2x
we get sin2x = aa+b hence cos2x = ba+b
now substituting these values in sin12xa5 + cos12xb5
we get value as 1(a+b)5