C in a Nutshell

Name

tan

Synopsis

Calculates the tangent of an angle

#include <math.h>
doubletan( double x );
float tanf( float x );        (C99)
long double tanl( long double x );        (C99)

The tan() function calculates the tangent of the angle represented by its argument x as a number of radians.

Example

const double pi = 4.0L * atan( 1.0 );         // Because tan(pi/4) = 1
double shadow_length = 85.5,
       angle = 36.2;          // Sun's elevation from the horizon, in
                              // degrees
double height = shadow_length *tan( angle * pi/180);

printf("The tower is %.2f meters high.\n", height);

This code produces the following output:

The tower is 62.58 meters high.

See Also

sin(), cos(), atan(); the tangent functions for complex numbers, ctan(), ctanf() and ctanl()