Check sibling questions

Ex 3.3, 14 - Chapter 3 Class 11 Trigonometric Functions

Last updated at May 29, 2023 by

Ex 3.3, 14 - Prove that sin 2x + 2sin 4x + sin 6x = 4cos2 x - cos x + cos y formula

Ex 3.3, 14 - Chapter 3 Class 11 Trigonometric Functions - Part 2

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class

Book a free demo

Transcript

Ex 3.3, 14 Prove that sin 2x + 2sin 4x + sin 6x = 4cos2 x sin 4x Taking L.H.S. sin 2x + 2sin 4x + sin 6x = (sin 6x + sin 2x) + 2sin 4x = 2 sin ((6 + 2 )/2) cos ((6 2 )/2) + 2sin 4x = 2 sin (8 /2) cos (4 /2) + 2sin 4x = 2 sin 4x cos 2x + 2sin 4x = 2 sin 4x (cos 2x + 1) = 2 sin 4x ( 2cos2x 1 + 1) = 2 sin 4x (2cos2x) = 4 sin 4x cos2x = R.H.S Hence L.H.S = R.H.S Hence proved

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.