If $y=57e^{6x}+39e^{-6x}$ then $\frac{d^2y}{dx^2}$ is equal to :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $36y$
$y=57e^{6x}+39e^{-6x}$
$\frac{dy}{dx}=57e^{6x}×6+39e^{-6x}×-6$
$⇒\frac{d^2y}{dx^2}=57e^{6x}×36+39e^{-6x}×36$
$=36(57e^{6x}+39e^{-6x})$
$=36y$