Standard C Library

Syntax:
```
double acos(double x)
```
Description:
The acos() function calculates the arc cosine of x; that is the value whose cosine is x. If x falls outside the range -1 to 1, acos() fails and errno is set.
Returns:
The acos() function returns the arc cosine in radians and the value is mathematically defined to be between 0 and PI (inclusive).

Syntax:
```
double asin(double x)
```
Description:
The asin() function calculates the arc sine of x; that is the value whose sine is x. If x falls outside the range -1 to 1, asin() fails and errno is set.
Returns:
The asin() function returns the arc sine in radians and the value is mathematically defined to be between -PI/2 and PI/2 (inclusive).

Syntax:
```
double atan(double x)
```
Description:
The atan() function calculates the arc tangent of x; that is the value whose tangent is x.
Returns:
The atan() function returns the arc tangent in radians and the value is mathematically defined to be between -PI/2 and PI/2 (inclusive).

Syntax:
```
double atan2(double y, double x)
```
Description:
The atan2() function calculates the arc tangent of the two variables x and y. It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result.
Returns:
The atan2() function returns the result in radians, which is between -PI and PI (inclusive).

Syntax:
```
double ceil(double x)
```
Description:
These functions round x up to the nearest integer.
Returns:
The rounded integer value. If x is integral or infinite, x itself is returned.

Syntax:
```
double cos(double x)
```
Description:
The cos() function returns the cosine of x, where x is given in radians.
Returns:
The cos() function returns a value between -1 and 1.

Syntax:
```
double cosh(double x)
```
Description:
The cosh() function returns the hyperbolic cosine of x, which is defined mathematically as (exp(x) + exp(-x)) / 2.
Returns:
The cosh() function returns a double value.

Syntax:
```
double exp(double x)
```
Description:
The exp() function returns the value of e (the base of natural logarithms) raised to the power of x.
Returns:
The exp() function returns a double value.

Syntax:
```
double fabs(double x)
```
Description:
The fabs() functions return the absolute value of the floating-point number x.
Returns:
The fabs() function returns a double value.

Syntax:
```
double floor(double x)
```
Description:
These functions round x down to the nearest integer.
Returns:
The rounded integer value. If x is integral or infinite, x itself is returned.

Syntax:
```
double fmod(double x, double y)
```
Description:
The fmod() function computes the remainder of dividing x by y. The return value is x - n * y, where n is the quotient of x / y, rounded towards zero to an integer.
Returns:
The fmod() function returns the remainder, unless y is zero, when the function fails and errno is set.

Syntax:
```
double frexp(double x, int* exp)
```
Description:
The frexp() function is used to split the number x into a normalized fraction and an exponent which is stored in exp.
Returns:
The frexp() function returns the normalized fraction. If the argument x is not zero, the normalized fraction is x times a power of two, and its absolute value is always in the range 1/2 (inclusive) to 1 (exclusive). If x is zero, then the normalized fraction is zero and zero is stored in exp.

Syntax:
```
double ldexp(double x, int exp)
```
Description:
The ldexp() function returns the result of multiplying the floating-point number x by 2 raised to the power exp.
Returns:
The ldexp() function returns a double value.

Syntax:
```
double log(double x)
```
Description:
The log() function returns the natural logarithm of x.
Returns:
The log() function can return the following errors:
- EDOM: The argument x is negative
- ERANGE: The argument x is zero. The log of zero is not defined (minus infinity).

Syntax:
```
double log10(double x)
```
Description:
The log() function returns the base-10 logarithm of x.
Returns:
The log() function can return the following errors:
- EDOM: The argument x is negative
- ERANGE: The argument x is zero. The log of zero is not defined (minus infinity).

Syntax:
```
double modf(double x, double* iptr)
```
Description:
The modf() function breaks the argument x into an integral part and a fractional part, each of which has the same sign as x. The integral part is stored in iptr.
Returns:
The modf() function returns the fractional part of x.

Syntax:
```
double pow(double x, double y)
```
Description:
The pow() function returns the value of x raised to the power of y.
Returns:
The pow() function can return the following error:
- EDOM: The argument x is negative and y is not an integral value. This would result in a complex number.

Syntax:
```
double sin(double x)
```
Description:
The sin() function returns the sine of x, where x is given in radians.
Returns:
The sin() function returns a value between -1 and 1.

Syntax:
```
double sinh(double x)
```
Description:
The sinh() function returns the hyperbolic sine of x, which is defined mathematically as (exp(x) - exp(-x)) / 2.
Returns:
The sin() function returns a double value.

Syntax:
```
double sqrt(double x)
```
Description:
The sqrt() function returns the non-negative square root of x. It fails and sets errno to EDOM, if x is negative.
Returns:
The sqrt() function can return the following error:
- EDOM: The argument x is negative.

Syntax:
```
double tan(double x)
```
Description:
The tan() function returns the tangent of x, where x is given in radians.
Returns:
The sqrt() function returns a double value.

Syntax:
```
double tanh(double x)
```
Description:
The tanh() function returns the hyperbolic tangent of x, which is defined mathematically as sinh(x) / cosh(x).
Returns:
The tanh() function returns a double value.