${\displaystyle \cot(90-\alpha )=\tan \alpha }$  

${\displaystyle \cot(90+\alpha )=-\tan \alpha }$  

${\displaystyle \cot(180-\alpha )=-\cot \alpha }$  

${\displaystyle \cot(180+\alpha )=\cot \alpha }$  

${\displaystyle \cot(270-\alpha )=\tan \alpha }$  

${\displaystyle \cot(270+\alpha )=-\tan \alpha }$  

${\displaystyle \cot(360-\alpha )=-\cot \alpha }$  

${\displaystyle \cot(360+\alpha )=\cot \alpha }$  

${\displaystyle \cot(\alpha +\beta )={\frac {1-\cot \alpha *\cot \beta }{\cot \alpha +\cot \beta }}}$  

${\displaystyle \cot(\alpha -\beta )={\frac {1+\cot \alpha *\cot \beta }{\cot \alpha -\cot \beta }}}$  

${\displaystyle \cot 2\alpha =-{\frac {1-\cot ^{2}\alpha }{2\cot \alpha }}}$  

${\displaystyle \cot(\alpha /2)={\frac {\sin \alpha }{1-\cos \alpha }}}$  

${\displaystyle \cot(\alpha /2)={\frac {1+\cos 2\alpha }{\sin 2\alpha }}}$  

${\displaystyle \cot \alpha +\cot \beta ={\frac {\sin(\alpha +\beta )}{\sin \alpha *\sin \beta }}}$  

${\displaystyle \cot \alpha -\cot \beta =-{\frac {\sin(\alpha -\beta )}{\sin \alpha *\sin \beta }}}$  

${\displaystyle \cot ^{2}\alpha ={\frac {1+\cos 2\alpha }{1-\cos 2\alpha }}}$  

• Triqonometriya

• With interactive animation
• - An interactive simulation