Answer
The derivative is $\frac{x\cos(x)-2\sin(x)}{x^3}$.
Work Step by Step
Using the quotient rule: $g'(x)=(\frac{u(x)}{v(x)})'=\frac{u'(x)v(x)-v'(x)u(x)}{(v(x))^2}$
$u(x)=sin(x); u'(x)=cos(x)$
$v(x)=x^2; v'(x)=2x$
$g'(x)=\frac{(cos(x)(x^2)-(sin(x))(2x)}{(x^2)^2}=$
$\frac{x(xcos(x)-2sin(x))}{x^4}=\frac{x\cos(x)-2\sin(x)}{x^3}$