Examples

Chapter 3 Class 11 Trigonometric Functions
Serial order wise

This video is only available for Teachoo black users

Get live Maths 1-on-1 Classs - Class 6 to 12

### Transcript

Example 22 Solve tan 2x = – cot (x" + " 𝜋/3) tan 2x = –cot (𝑥" + " 𝜋/3) We need to make both in terms of tan Rough tan (90° + θ) = –cot θ –cot θ = tan (90° + θ) –cot θ = tan (𝜋/2 " + θ" ) Replacing θ by x + 𝜋/3 –cot ("x + " 𝜋/3) = tan (𝜋/2 "+ x +" 𝜋/3) tan 2x = tan (𝜋/2+x" + " 𝜋/3) tan 2x = tan (𝜋/2 " + " 𝜋/3 " + x" ) tan 2x = tan ((3𝜋 + 2𝜋)/(2 × 3) " + x" ) tan 2x = tan (5𝜋/6 " + x" ) General solution Let tan x = tan y tan 2x = tan 2y From (1) and (2) tan 2y = tan (5𝜋/6 " + x" ) 2y = 5𝜋/6 + x General solution is 2x = nπ + 2y where n ∈ Z Put 2y = ("x + " 5𝜋/6) 2x = nπ + ("x + " 5𝜋/6) 2x – x = nπ + 5𝜋/6 x = nπ + 𝟓𝝅/𝟔 where n ∈ Z

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.