Given that cosec θ – sin θ = b3 and sec θ – cos θ = a3 Solving the first equation we get, 1/ sin θ – sin θ = b3 This gives (1-sin2θ) / sin θ = b3 This yields cos2θ/ sin θ = b3 Similarly, solving the second equation on similar lines gives sin2θ/ cos θ = a3 Now, considering L.H.S a4b2 + a2b4 = (sin2θ/ cos θ)4/3 . (cos2θ/ sin θ)2/3 + (sin2θ/ cos θ)2/3 . (cos2θ/ sin θ)4/3 On simplifying this we get, = sin 2θ + cos2θ = 1. Hence, a4b2 + a2b4 = 1.