

Introducing your new favourite teacher - Teachoo Black, at only βΉ83 per month
(x + y) formula
Last updated at Feb. 12, 2020 by Teachoo
Ex 3.3, 22 Prove that cot π₯ cot 2π₯ β cot 2π₯ cot 3π₯ β cot 3π₯ cot π₯ = 1 Taking L.H.S. cot x cot 2x β cot 2x cot 3x β cot 3x cot x = cot x cot 2x β cot 3x (cot 2x + cot x) = cot x cot 2x β cot (2x + x) (cot 2x + cot x) = cot x cot 2x β ((cot 2x cot x β 1)/(cot x + cot 2x)) (cot 2x + cot x) = cot x cot 2x β (cot 2x cot x β 1) = cot x cot 2x β cot 2x cot x + 1 = 1 = R.H.S. Hence L.H.S = R.H.S Hence proved