Cofunction Calculator

°
Math

The Cofunction Calculator applies the cofunction identities, which relate a trig function of an angle to the complementary function of its complement (90° − θ). Enter an angle and function.

Formula

sin θ = cos(90° − θ), tan θ = cot(90° − θ), sec θ = csc(90° − θ)
  • Cofunctions of complementary angles are equal.
  • The complement of θ is 90° − θ (or π/2 − θ in radians).

sin 30°

Inputs
  • Angle: 30 °
  • Function: sin

sin 30° = cos 60° = 0.5.

Frequently asked questions

What are cofunction identities?
They state that a trig function of an angle equals its cofunction of the complementary angle, e.g. sin θ = cos(90° − θ).