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

 

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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.