AP EAMCET2008MathematicsDifferentiation
If y= ( _e x ) , then x^2 d^2 y d x^2 +x d y d x is equal to
Options
- A( _e x )
- B( _e x )
- Cy^2
- D-y
Correct answer
D. -y
Step-by-step solution
Given that, y= ( _e x ) On differentiating w.r.t. x , we get d y d x = ( _e x ) 1 x Again differentiating, we get aligned d^2 y d x^2 & = -x ( _e x ) 1 x - ( _e x ) 1 x^2 & = - ( _e x )- ( _e x ) x^2 aligned Now, x^2 d^2 y d x^2 +x d y d x aligned & = x^2 [- ( _e x )- ( _e x ) ] x^2 & =- ( _e x ) & =-y [from Eq. (i)] aligned