Given cosec x – sin x = a3
We know that cosec x = 1/ sin x.

We know that 1 – sin2x = cos2x

Also given secx – cosx = b3
We know that sec x = 1/ cos x

We know that 1 – cos2x = sin2x

Consider LHS = a2b2 (a2 + b2)

We know that cos2 x+ sin2x = 1
= 1
= RHS
Hence proved.