The correct option is C (α+β)(α2+β2)
α32cosec212(tan−1αβ)+β32sec2(12tan−1βα)
=α32sin212(tan−1αβ)+β32cos212(tan−1βα)
=α31−cos(tan−1αβ)+β31+cos(tan−1βα)
Put tan−1αβ=cos−1β√α2+β2 and tan−1βα=cos−1α√α2+β2
=α31−cos(cos−1β√α2+β2)+β31+cos(cos−1α√α2+β2)
=α31−β√α2+β2+β31+α√α2+β2
=√α2+β2[α3√α2+β2−β+β3√α2+β2+α]
=√α2+β2[α3√α2+β2−β×√α2+β2+β√α2+β2+β+β3√α2+β2+α×√α2+β2−α√α2+β2−α]
=√α2+β2[α(√α2+β2+β)+β(√α2+β2−α)]
=√α2+β2[α√α2+β2+β√α2+β2]
=(α+β)(α2+β2)