How would I prove the following two trigonometric identity.
$$\cot A\sin 2A=1+\cos 2A$$
This is my work so far
$$\frac{\cos A}{\sin A}(2\sin A \cos A)=1+\cos 2A$$
I am not sure what I would do next to make them equal.
[Math] Prove $\cot A\sin 2A=1+\cos 2A$
trigonometry
Best Answer
\begin{eqnarray*} cotAsin2A=\frac{cosA}{sinA}(2sinAcosA)=cosA(2cosA)=2cos^2A=1+cos2A \end{eqnarray*}
This should be everything.