### Trigonometry

goals
$\displaystyle \left( \sin { \theta } +\cos { \theta } \right) \left( 1-\sin { \theta } \cos { \theta } \right)$ can be written as :
If the angles of elevaton of the top of a tower from two points distance s and t $\displaystyle \left ( s> t \right )$ from its foot are $\displaystyle 30^{0}$ and $\displaystyle 60^{0}$ respectively then the height of the tower is