- $\tan\theta+\cot\theta=\dfrac{2}{\sin2\theta}$
Left Side:
$\begin{align*} \tan\theta+\cot\theta={\sin\theta\over\cos\theta}+{\cos\theta\over\sin\theta}={\sin^2\theta+\cos^2\theta\over\cos\theta\sin\theta} = \dfrac{1}{1\sin\theta\cos\theta} \end{align*}$ Right Side:
$\begin{align*} \dfrac{2}{\sin2\theta}=\dfrac{2}{2\sin\theta\cos\theta}=\dfrac{1}{1\cos\theta\sin\theta} \end{align*}$
I got it now. Thanks!