How do I solve [math]\int sec^2 \frac{\pi}{3} +sin \frac{x}{2} \hspace{0.2cm} \mathrm d x[/math]?
How can I solve  [math]\frac{1}{x} +\frac{1}{y} =\frac{1}{3} [/math] and [math]\frac{x^2}{y} +\frac{y^2}{x} =12 [/math]?