I really need help with this task:

Determine vector of height $\displaystyle h_a$ from top A in triangle ABC if $\displaystyle \vec BC$$\displaystyle =$ $\displaystyle \vec m$ $\displaystyle + 2*\vec n$ and $\displaystyle \vec CA$$\displaystyle = 2* \vec m$ $\displaystyle - \vec n$ $\displaystyle |\vec m | = | \vec n | = \sqrt 3$ and angle between vectors $\displaystyle \vec m$ and $\displaystyle \vec n = \pi/2$.