If y=36 e^5 x+47 e^-5 x, then

The correct answer is Option () - 

$y=36e^{5x}+47e^{-5x}.$

$\frac{dy}{dx}=36\cdot5e^{5x}-47\cdot5e^{-5x}=180e^{5x}-235e^{-5x}.$

$\frac{d^2y}{dx^2}=180\cdot5e^{5x}+235\cdot5e^{-5x}=900e^{5x}+1175e^{-5x}.$

$\frac{d^2y}{dx^2}=25(36e^{5x}+47e^{-5x}).$

$\frac{d^2y}{dx^2}=25y.$