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Trigonometric Symbols

Last Updated : 16 Jun, 2026

Trigonometric Symbols are mathematical symbols used to represent angles, trigonometric functions, inverse functions, and other quantities commonly used in trigonometry.

Common Trigonometric Symbols

In trigonometry, there are many functions used to relate angles within a right triangle to its various lengths or ratios.

Trigonometric Symbol

Trigonometric Symbol Name

Explanation

θ

Theta

It is used to represent an angle in trigonometric equations.

α

Alpha

Represents an angle

sin

Sine

It is represented as "sin(θ)."

cos

Cosine

It is represented as "cos(θ)."

tan

Tangent

It is represented as "tan(θ)."

csc

Cosecant

The angle of cosecant is the reciprocal of the sine, csc(θ) = 1/sin(θ).

sec

Secant

The angle of a secant is the reciprocal of the cosine, sec(θ) = 1/cos(θ).

cot

Cotangent


The angle of cotangent is the reciprocal of the tangent, cot(θ) = 1/tan(θ).

arcsin x or sin⁻¹(x)

Arcsine function or Inverse sine

It is used to find the angle for a given trigonometric ratio

arccos x or cos⁻¹(x)

Arccos function or Inverse cosine

It is used to find the angle for a given trigonometric ratio

arctan x or tan⁻¹(x)

Arctan function or Inverse tan

It is used to find the angle for a given trigonometric ratio

π

Pi

It is used in trigonometry to express angles in radians.

r

Radius

In polar coordinates, r represents the distance from the origin to a point, which is used in trigonometry when dealing with polar coordinates.

Δ

Delta

It is used to represent the change in an angle, such as Δθ

Trigonometric Symbols in Right-Angled Triangle

There are 6 basic trigonometric relations that form the basics of trigonometry. These 6 trigonometric relations are ratios of all the different possible combinations in a right-angled triangle.

Trigonometric Symbols of θ

Trigonometric Function in Right-Angled Triangle

Sine (sin θ)

sin θ = perpendicular/hypotenuse

Cosine (cos θ)

cos θ = base/hypotenuse

Tangent (tan θ)

tan θ = perpendicular/base

Cosecant (csc θ)

csc θ = hypotenuse/perpendicular

secant (sec θ)

sec θ = hypotenuse/base

cotangent (cot θ)

cot θ = base/hypotenuse

Symbols Used in Radian Measure

Angles can be measured in degrees or radians. Trigonometry frequently uses radians because many mathematical formulas are simpler in radian form.

Pi Symbol (π): The symbol π (Pi) is approximately equal to \piwhen

The relationship between degrees and radians is 180^\circ=\pi

Common Angle Conversions

The symbol π is fundamental in trigonometry and circular geometry.

Degrees (°)Radians
0
30°
45°
60°
90°
120°
180°
360°

Symbols Used in Polar Coordinates

Polar coordinates describe the position of a point using a distance and an angle.

The two main symbols are the following:

  • r = distance from origin
  • θ = Angle measured from the positive x-axis

A point in polar coordinates is written as (r,\theta).

Solved Examples

Example 1: What does the symbol "sec θ" represent?

Secant is the reciprocal of cosine.

Example 2: Find the value of \sin^{-1}\left(\frac{1}{2}\right).

The angle whose sine value is 1/2 is :

Example 3: Convert 180° into radians.

Practice Questions

  1. Which symbol is commonly used to represent an angle in trigonometry?
  2. What is the reciprocal of sin θ?
  3. What is the reciprocal of tan θ?
  4. Which symbol represents the radius in polar coordinates?
  5. What is the value of 360° in radians?

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