Change tan A to sin A/cos A and cot A to cos A/ sin A for easier manipulation.

Find common denominators and simplify the fractions.

Use the trigonometric identity and change cos^{2}x + sin^{2}x = 1.

Prove Trigonometric Identities involving Cotangent and Tangent . Additional Math Tuition. Woodlands, Choa Chu Kang, Yew Tee, Sembawang and Johor Bahru.