To prove the identity \(\cot \theta + \tan \theta \equiv 2 \csc 2\theta\), we start by expressing each term in terms of sine and cosine:
\(\cot \theta = \frac{\cos \theta}{\sin \theta}, \quad \tan \theta = \frac{\sin \theta}{\cos \theta}\)
Thus,
\(\cot \theta + \tan \theta = \frac{\cos \theta}{\sin \theta} + \frac{\sin \theta}{\cos \theta}\)
Combine the fractions:
\(\frac{\cos^2 \theta + \sin^2 \theta}{\sin \theta \cos \theta}\)
Using the Pythagorean identity \(\cos^2 \theta + \sin^2 \theta = 1\), we have:
\(\frac{1}{\sin \theta \cos \theta}\)
Now, express \(\csc 2\theta\):
\(\csc 2\theta = \frac{1}{\sin 2\theta}\)
Using the double angle identity \(\sin 2\theta = 2 \sin \theta \cos \theta\), we get:
\(\csc 2\theta = \frac{1}{2 \sin \theta \cos \theta}\)
Therefore,
\(2 \csc 2\theta = \frac{2}{2 \sin \theta \cos \theta} = \frac{1}{\sin \theta \cos \theta}\)
Thus, \(\cot \theta + \tan \theta = 2 \csc 2\theta\), proving the identity.