If $\mathrm{Tan}{40}^{\circ }+2 \mathrm{Tan}{10}^{\circ }=\mathrm{Cotx}$ then $\mathrm{x}=$

$\begin{array}{rcl}\tan {40}^0+2{\tan }^{{40}^0}& =& \cot \mathrm{x}\\ \tan ({50}^0-{40}^0)& =& \tan {10}^0\\ \frac{\tan {50}^0-\tan {40}^0}{1+\tan {50}^0\tan {40}^0}& =& \tan {10}^0\\ \frac{\tan {50}^0-\tan {40}^0}{1+1}& =& \tan {10}^0\\ \tan {50}^0-\tan {40}^0& =& 2\tan {10}^0\\ \tan {40}^0+2\tan {10}^0& =& \tan {50}^0\\ & =& \cot {40}^0\end{array}$