Ex. 61. Given the sides $b$ and $c$ of a triangle and the median $m_{a}$, determine the other medians.
Ex. 61. $m_{b}=\frac{1}{2} \sqrt{3 b^{2}+6 c^{2}-8 m_{a}^{2}}, m_{c}=\frac{1}{2} \sqrt{6 b^{2}+3 c^{2}-8 m_{a}^{2}}$.