C - Purpose of math.h

In C, math.h is the Mathematics Header File.
It provides function prototypes and macros for performing mathematical calculations — like powers, roots, trigonometry, rounding, logarithms, and more.

1. Purpose of `math.h`

When you include:

#include <math.h>

you gain access to:

Standard mathematical functions (square root, sine, cosine, logarithms, etc.).
Common mathematical constants (like INFINITY, NAN in C99).
Macros for special floating-point values.

2. Important Notes

Most math.h functions work with double by default (variants exist for float and long double in C99, like sqrtf() and sqrtl()).
To compile a program using these functions on some compilers (like GCC), you may need to link the math library with -lm:
```
gcc program.c -o program -lm
```

3. Commonly Used Functions

a) Basic Arithmetic

Function	Description
`sqrt(x)`	Square root
`cbrt(x)` (C99)	Cube root
`pow(x, y)`	x raised to the power y
`fabs(x)`	Absolute value (floating-point)
`fmod(x, y)`	Floating-point remainder (x mod y)

b) Trigonometric Functions

Function	Description
`sin(x)`	Sine (x in radians)
`cos(x)`	Cosine
`tan(x)`	Tangent
`asin(x)`	Arc sine
`acos(x)`	Arc cosine
`atan(x)`	Arc tangent
`atan2(y, x)`	Arc tangent of y/x considering quadrants

c) Exponential and Logarithmic

Function	Description
`exp(x)`	e raised to the power x
`log(x)`	Natural logarithm (base e)
`log10(x)`	Base-10 logarithm
`log2(x)` (C99)	Base-2 logarithm

d) Rounding and Remainder

Function	Description
`ceil(x)`	Rounds up to nearest integer
`floor(x)`	Rounds down to nearest integer
`round(x)` (C99)	Rounds to nearest integer (ties to even)
`trunc(x)` (C99)	Truncates fractional part

e) Hyperbolic Functions

Function	Description
`sinh(x)`	Hyperbolic sine
`cosh(x)`	Hyperbolic cosine
`tanh(x)`	Hyperbolic tangent

4. Example

#include <stdio.h>
#include <math.h>

int main() {
    double num = 16.0;
    printf("Square root of %.2f = %.2f\n", num, sqrt(num));
    printf("2 raised to 3 = %.2f\n", pow(2, 3));
    printf("Sine of 90 degrees = %.2f\n", sin(M_PI / 2)); // M_PI = 3.14159...
    printf("Log base 10 of 1000 = %.2f\n", log10(1000));
    return 0;
}