In C, acosh() returns the inverse hyperbolic cosine of x. acosh(1) is 0. Larger inputs give a larger result.
You pass one double, and it must be 1 or greater. The result is a double that is 0 or greater. Include <math.h>.
Pass a value of 1 or more. Start with this call.
acosh(1.0);| Call | What it does |
|---|---|
acosh(1.0) | Returns 0, the smallest result this function gives. |
Include <math.h>. On GCC, link with -lm.
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);| Parameter | Description |
|---|---|
| x | Required. A double that is 1 or greater. |
| Return Value | Description |
|---|---|
| Inverse hyperbolic cosine | A double that is 0 or greater. |
| NaN | Returned when x is less than 1. |
acosh ValuesPrint results for the endpoint 1 and a larger input.
#include <math.h>
#include <stdio.h>
int main(void) {
printf("acosh(1) = %.5f\n", acosh(1.0));
printf("acosh(2) = %.5f\n", acosh(2.0));
return 0;
}acosh; link with -lm on GCC.acosh(1) is 0 because cosh(0) = 1.acosh(2) ≈ 1.31696.coshRound-trip a value: acosh then cosh should recover the original x.
#include <math.h>
#include <stdio.h>
int main(void) {
double x = 2.5;
double t = acosh(x);
printf("acosh(%.1f) = %.5f\n", x, t);
printf("cosh(t) = %.5f\n", cosh(t));
return 0;
}2.5 is in the domain.t.cosh(t) returns to 2.5.Compare the library result with ln(x + sqrt(x*x - 1)) using log and sqrt.
#include <math.h>
#include <stdio.h>
int main(void) {
double x = 2.0;
double lib = acosh(x);
double hand = log(x + sqrt(x * x - 1.0));
printf("acosh(2) = %.10f\n", lib);
printf("ln formula = %.10f\n", hand);
return 0;
}acosh(2) uses a carefully coded implementation.log + sqrt express the same math identity.Compute the inverse sine and get an angle in radians.
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