## What is acos in c programming?

acos in c is a mathematical function which is used to find arc cosine of a given number in radians.

This function is defined in math.h header file.

### Prototype

```
#include<math.h>
double acos(double y);
```

### Parameter

acos function takes floating point value as angle in radians.

### Return value

This function returns arc cosine of a given number.

## Example program for acos in c

```
#include <stdio.h>
#include <math.h>
#define PI 3.14
int main()
{
double x, res, val1;
x=35.0;
val1=PI/180;
res=acos(x*val1);
printf("The arc cosine of %lf is %lf degrees", x, res);
return 0;
}
```

While using gcc use below command to add math header.

`gcc file_name.c -lm`

### Code explanation

The variable val1 is defined in terms of degrees and passed to the acos function along with the input value. The result is printed onto the console.

## Difference between acos and cos in c

acos in c is a mathematical function that is used to find the arc cosine of a given number in radians. cos in c is a mathematical function that is used to find the cosine of a given number.

Prototypes are as follows

```
double acos(double y);
double cos(double y);
```

acos in c | cos in c |

Used to find arc cosine of a given number. | Used to find cosine of a given number. |

`double acos(double y);` | `double cos(double y);` |

## Difference between acos and cosh in c

acos in c is a mathematical function that is used to find the arc cosine of a given number in radians. cosh in c is used to find the hyperbolic cosine of a given number.

Prototypes are as follows

```
double acos(double y);
double cosh(double y);
```

acos in c | cosh in c |

Used to find arc cosine of a given number. | Used to find hyperbolic cosine of a given number. |

double acos(double y); | double cosh(double y); |

## People also ask for

### What is acos in c?

acos in c is a mathematical function that is used to find the arc cosine of a given number in radians. It is defined in math.h header file.