This is an important question from the
Book- ML Aggarwal
Chapter- Trigonometric Identities
We have to prove that
(i) (1 + tan A)/ sin A + (1 + cot A)/ cos A = 2 (sec A + cosec A) (ii) sec4 A – tan4 A = 1 + 2 tan2 A
Trigonometric Identities, class 10th, chapter 18th, question no 25, ICSE board, ML aggarwal..