If y=sin x+ex,then d2xdy2=
sin x−ex(cos x+ex)3
y=sin x+ex⇒dydx=cos x+ex
⇒dxdy=(cos x+ex)−1 ⋯(i)
d2xdy2=−(cos x+ex)−2(−sin x+ex)dxdy
Substituting the value of dydx from (i)
d2xdy2=(sin x−ex)(cos x+ex)2(cos x+ex)−1=sin x−ex(cos x+ex)3