What Is a Trigonometric Identity

Trigonometric identities are equations involving the trigonometric functions that are true for every value of the variables involved. Some of the most commonly used trigonometric identities are derived from the Pythagorean Theorem , like the following: sin2(x)+cos2(x)=1. 1+tan2(x)=sec2(x)

What are the basic trigonometric identities?

• Sin θ = 1/Csc θ or Csc θ = 1/Sin θ
• Cos θ = 1/Sec θ or Sec θ = 1/Cos θ
• Tan θ = 1/Cot θ or Cot θ = 1/Tan θ

What are the 3 basic trigonometric identities?

There are three basic trigonometric ratios: sine , cosine , and tangent .