cis

Compute the cosine and sine of x at the same time and return the results as a complex number.

Interface Definition

C interface:

float complex cisf(float x);

double complex cis(double x);

Parameters

Parameter	Type	Description	Input/Output
x	For cisf, x is of single-precision floating-point type. For cis, x is of double-precision floating-point type.	Floating-point value of the input data.	Input

Parameter

Type

Description

Input/Output

For cisf, x is of single-precision floating-point type.

For cis, x is of double-precision floating-point type.

Floating-point value of the input data.

Input

Return Value

A complex number y is returned as the cosine and sine results of x. y.real ∈ [–1, +1]; y.imag ∈ [–1, +1]

If the input x is +0, the output y.real is +0 and y.imag is +1.
If the input x is –0, the output y.real is –0 and y.imag is +1.
If the input x is ±∞, the output y.real and y.imag are both NaN.
If the input x is NaN, the output y.real and y.imag are both NaN.

Dependency

C: "kc.h"

Example

C interface:

    // typical usage
    double x1 = INFINITY;
    double x2 = 2.0;
    double x3 = -2.5;
    double x4 = NAN;
    double x5 = 0.0;
    double complex z1 = cis(x1);
    double complex z2 = cis(x2);
    double complex z3 = cis(x3);
    double complex z4 = cis(x4);
    double complex z5 = cis(x5);
    // print result
    printf("/*\n");
    printf(" * cis(%.2f) = %.6f + %.6f*I\n", x1, __real__(z1), __imag__(z1));
    printf(" * cis(%.2f) = %.6f + %.6f*I\n", x2, __real__(z2), __imag__(z2));
    printf(" * cis(%.2f) = %.6f + %.6f*I\n", x3, __real__(z3), __imag__(z3));
    printf(" * cis(%.2f) = %.6f + %.6f*I\n", x4, __real__(z4), __imag__(z4));
    printf(" * cis(%.2f) = %.6f + %.6f*I\n", x5, __real__(z5), __imag__(z5));
    printf(" **/\n");
 
   /*
    * cis(inf) = nan + nan*I
    * cis(2.00) = 0.909297 + -0.416147*I
    * cis(-2.50) = -0.598472 + -0.801144*I
    * cis(nan) = nan + nan*I
    * cis(0.00) = 0.000000 + 1.000000*I
    **/

Parent topic: Complex Functions