Secant Calculator

How it works

1. 1Enter an angle θ and choose Degrees or Radians.
2. 2Secant is sec(θ) = 1 ÷ cos(θ); it is undefined whenever cos(θ) = 0 (θ = 90°, 270°, …).
3. 3Cosecant is csc(θ) = 1 ÷ sin(θ); it is undefined whenever sin(θ) = 0 (θ = 0°, 180°, …). Both show — at those asymptotes.

Use cases

• Solving right-triangle and unit-circle problems that involve reciprocal trig ratios.
• Verifying identities such as sec²θ − tan²θ = 1.
• Physics and engineering calculations where sec or csc appear in wave or optics formulas.

Frequently asked questions

What is the secant function?

Secant is the reciprocal of cosine: sec(θ) = 1 ÷ cos(θ). It is undefined at angles where cos(θ) = 0, such as 90° and 270°.

What is the cosecant function?

Cosecant is the reciprocal of sine: csc(θ) = 1 ÷ sin(θ). It is undefined where sin(θ) = 0, such as 0° and 180°.

Why does the result show — for some angles?

The dash indicates the function is undefined there because its denominator equals zero — a vertical asymptote on the graph.