TeX source:

\frac{\mathrm{d}}{\mathrm{dx}} \frac{\cos (\mathrm{x})}{\mathrm{x}^{2}}=\frac{\mathrm{x}^{2}(-\sin (\mathrm{x}))-(\cos (\mathrm{x}))(2 \mathrm{x})}{\left(\mathrm{x}^{2}\right)^{2}}=-\frac{\mathrm{x} \sin (\mathrm{x})+2 \cos (\mathrm{x})}{\mathrm{x}^{3}}