Trigonometric Identities are

  1. cos 2  θ + sin 2  θ = 1
  2. 1 + tan 2  θ = sec 2  θ
  3. 1 + cot 2  θ = cosec 2  θ

trigonometric identities.jpg.png

 

How do we remember them?

We should only remember

cos 2  θ + sin 2  θ = 1

 

For other identities,

just divide by sin 2  θ or cos 2  θ  

 

cos 2  θ + sin 2  θ = 1

Divide by  cos 2  θ  

cos 2  θ/cos 2  θ + sin 2  θ/cos 2  θ = 1/cos 2  θ

1 + tan 2  θ = sec 2  θ

 

cos 2  θ + sin 2  θ = 1

Divide by  sin 2  θ  

cos 2  θ/sin 2  θ + sin 2  θ/sin 2  θ = 1/cosec 2  θ

cot 2  θ + 1 = cosec 2  θ

 

  1. Chapter 8 Class 10 Introduction to Trignometry
  2. Concept wise
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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.