If y=x^3log x, then (d^2y)/(dx^2) is :

The correct answer is Option (3) → $x(5 + 6\log x)$

$y=x^3\log x$

$⇒\frac{dy}{dx}=3x^2\log x+x^2$

$⇒\frac{d^2y}{dx^2}=3(2x\log x+x)+2x$

$=6x\log x+5x$

$=x(6\log x+5)$