cotd

Compute the cotangent of the input angle.

Interface Definition

C interface:

float cotdf(float x);

double cotd(double x);

long double cotdl(long double x);

Parameters

Parameter	Type	Description	Input/Output
x	For cotdf, x is of single-precision floating-point type. For cotd, x is of double-precision floating-point type. For cotdl, x is of long double-precision floating-point type.	Floating-point value representing an angle.	Input

Return Value

Normal range: The cotangent y of angle x is returned, that is, y = cot(x * π/180). y ∈ [-∞, +∞]
If the input x = 180 * k (k is an integer), the output is ±inf.
If the input x = 180 * k + 90 (k is an integer), the output is ±0.
If the input |x| = inf or NaN, the output is NaN.

Dependency

C: "km.h"

Example

C interface:

    // typical usage
    float x1 = -1.0, x2 = 1.0, x3 = 0.5, x4 = -0.5;
    // special handling
    float a = 0.0, b = INFINITY, c = -INFINITY, d = NAN;
    // print result
    printf("cotd(1.0) = %.15f\n", cotd(x1));
    printf("cotd(-1.0) = %.15f\n", cotd(x2));
    printf("cotd(0.5) = %.15f\n", cotd(x3));
    printf("cotd(-0.5) = %.15f\n", cotd(x4));
    printf("cotd(0.0) = %.15f\n", cotd(a));
    printf("cotd(-0.0) = %.15f\n", cotd(-a));
    printf("cotd(INFINITY) = %.15f\n", cotd(b));
    printf("cotd(-INFINITY) = %.15f\n", cotd(c));
    printf("cotd(NAN) = %.15f\n", cotd(d));
    /*
     *  cotd(1.0) = -57.289961630759421
     *  cotd(-1.0) = 57.289961630759421
     *  cotd(0.5) = 114.588650129309613
     *  cotd(-0.5) = -114.588650129309613
     *  cotd(0.0) = inf
     *  cotd(-0.0) = -inf
     *  cotd(INFINITY) = nan
     *  cotd(-INFINITY) = nan
     *  cotd(NAN) = nan
     *
     * */

Parent topic: Trigonometric Functions