Cosecant Calculator
Calculate csc(x), the reciprocal of sine, for an angle in degrees or radians.
Calculate cosecant
Choose the angle unit, enter a real angle, and evaluate its cosecant.
About the cosecant function
Cosecant is one of the six standard trigonometric functions. It is written as csc(x) and defined as the reciprocal of sine: csc(x) equals one divided by sin(x). On a right triangle, sine is the ratio of the side opposite an angle to the hypotenuse, so cosecant is the hypotenuse divided by the opposite side. This reciprocal relationship explains both the function's values and where it is undefined.
The calculator first converts a degree input to radians when needed, evaluates sine, and then takes its reciprocal. A radian input is used directly. Degrees divide a full rotation into 360 equal parts, while radians measure an angle by arc length relative to radius, giving 2 pi radians in a full rotation. Selecting the correct unit is essential because the same numeric input represents different angles in the two systems.
Cosecant is undefined whenever sine equals zero. That happens at integer multiples of 180 degrees, or integer multiples of pi radians. Near those angles, sine can be extremely small, so the magnitude of cosecant grows very large. The calculator treats values within a tiny floating-point tolerance of zero as undefined instead of displaying an unstable enormous approximation.
The range of real cosecant values is less than or equal to negative one or greater than or equal to positive one. It never lies strictly between negative one and one because sine itself always lies between negative one and one. Cosecant has the same sign as sine: it is positive in quadrants one and two and negative in quadrants three and four.
Like sine, cosecant is periodic. Its period is 360 degrees or 2 pi radians, so adding a complete rotation does not change the value. It is also an odd function, meaning csc of negative x is the negative of csc of x. These identities can simplify equations and provide useful checks on computed values.
Cosecant appears in trigonometric identities, calculus integrals, wave models, surveying, and geometry. The displayed sine value makes the reciprocal calculation transparent. Results are rounded to ten decimal places for readability, so exact special-angle values may be better expressed symbolically in formal work. For example, csc of 45 degrees is the square root of two even though its decimal is approximately 1.4142135624.
Cosecant examples
| Angle | Sine | Cosecant |
|---|---|---|
| 30 degrees | 0.5 | 2 |
| 90 degrees | 1 | 1 |
| 270 degrees | -1 | -1 |
| 0 degrees | 0 | Undefined |
How to calculate cosecant
- Enter the numeric angle to evaluate.
- Choose Degrees or Radians to match the angle's unit.
- Select Calculate cosecant to evaluate sine and take its reciprocal.
- Read the cosecant and supporting sine value, or the undefined-angle notice.
Frequently asked questions
What is the formula for cosecant?
Cosecant is the reciprocal of sine, so csc(x) equals 1 divided by sin(x). In a right triangle it is also the hypotenuse divided by the side opposite x.
When is cosecant undefined?
Cosecant is undefined wherever sine is zero. These angles are integer multiples of 180 degrees or pi radians.
Can cosecant be between negative one and one?
No, every real defined cosecant value has magnitude at least one. This follows because the magnitude of sine cannot exceed one.
What is the period of cosecant?
Cosecant repeats every 360 degrees or 2 pi radians. It inherits this period directly from the sine function.
Why does a near-zero angle produce a large result?
Sine approaches zero as the angle approaches a multiple of a half rotation. Taking the reciprocal of a very small number creates a value with very large magnitude.