Learn Class 10 Math - Introduction to Trigonometry

Trigonometry refers to the statement that includes the relationship between the sides and right angles. Major trigonometric ratios are sin, cos, cot, tan, cosine, sec, etc.

Main functions of Trigonometry

Generally, there are three main functions of trigonometry. These functions are given below:

  • Sin
  • Cos
  • Tan

Even or Odd functions of trigonometry

The odd trigonometric functions are the functions that refer to f(-x) = -f(x) and it is also symmetric to its origin. Whereas the even trigonometry functions are the functions in which f(-x) = f(x) and it is considered symmetric to the y-axis.

The following are some of the odd and even trigonometric functions:

  • Sin (-x) = - Sin x
  • Tan (-x) = -Tan x
  • Cos (-x) = Cos x
  • Csc (-x) = - Csc x
  • Cot (-x) = -Cot x
  • Sec (-x) = Sec x

Formulas of trigonometric functions

  • sin²θ + cos²θ = 1
  • Sec2θ = tan2θ + 1
  • Cosec2θ = cot2θ + 1
  • sin 2θ = 2 sin θ cos θ
  • cos²θ – sin²θ = cos 2θ
  • 2 tan θ / (1 – tan²θ) = tan 2θ
  • (cot²θ – 1) / 2 cot θ = cot 2θ

Identities of trigonometry

  • a2 + b2 – 2ab cos C = c2
  • b2 + c2 – 2bc cos A = a2
  • a2 + c2 – 2ac cos B = b2

These are all trigonometric functions, along with their identities.