acosh

接口定义

C interface：

float acoshf(float x);

double acosh(double x);

Fortran interface：

RES = ACOSHF(X);

RES = ACOSH(X);

参数

返回值

• 返回弧度角x的双曲反余弦函数值y，x ∈ [1, +∞)。
• 输入+1，返回+0。
• 输入x < +1，返回nan。
• 输入+∞，返回+∞。
• 输入-∞，返回nan。
• 输入nan，返回nan。

依赖

C: "km.h"

示例

C interface：

    double pi = acos(-1); 
    // typical usage 
    double a = pi/3, b = pi/2, c = -3*pi/4, d = 0.0; 
    // special handling 
    double e = INFINITY, f = -INFINITY, g = NAN; 
    // print result 
    printf("acosh(pi/3) = %.15f\n", acosh(a)); 
    printf("acosh(pi/2) = %.15f\n", acosh(b)); 
    printf("acosh(-3*pi/4) = %.15f\n", acosh(c)); 
    printf("acosh(0.0) = %.15f\n", acosh(d)); 
    printf("acosh(INFINITY) = %.15f\n", acosh(e)); 
    printf("acosh(-INFINITY) = %.15f\n", acosh(f)); 
    printf("acosh(NAN) = %.15f\n", acosh(g)); 
    /* 
     *  acosh(pi/3) = 0.306042108613265 
     *  acosh(pi/2) = 1.023227478547551 
     *  acosh(-3*pi/4) = nan 
     *  acosh(0.0) = nan
     *  acosh(INFINITY) = inf
     *  acosh(-INFINITY) = nan 
     *  acosh(NAN) = nan 
     * 
     * */

Fortran interface：

    REAL(8) :: X = 1.0 
    PRINT*,  ACOSH(X) 
    ! 
    ! OUTPUT 
    !     0.000000000000000 
    !