Fuente TeX:

\frac{1}{2}\dot{\theta}^2\Big|_{\dot{\theta}(\theta_A)}^{\dot{\theta}(\theta_B)}=\frac{g}{a}\text{cos}\theta\Big|_{\theta_A}^{\theta_B}+k\text{sen}^2\theta\Big|_{\theta_A}^{\theta_B}