Differentiating both sides two times w.r.t.
[By eq. (i)]……….(ii)
Again differentiating w.r.t. , ……….(iii)
Now from eq. (ii),
Putting this value of in eq. (iii),
Differentiating both sides two times w.r.t.
[By eq. (i)]……….(ii)
Again differentiating w.r.t. , ……….(iii)
Now from eq. (ii),
Putting this value of in eq. (iii),