C Language: tan function

In the C Programming Language, the tan function returns the tangent of x.


The syntax for the tan function in the C Language is:

double tan(double x);

Parameters or Arguments

A value expressed in radians (not degrees).


The tan function returns the tangent of x, measured in radians.

Required Header

In the C Language, the required header for the tan function is:

#include <math.h>

Applies To

In the C Language, the tan function can be used in the following versions:

  • ANSI/ISO 9899-1990

tan Example

/* Example using tan by TechOnTheNet.com */

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

int main(int argc, const char * argv[])
    /* Define temporary variables */
    double value;
    double result;
    /* Assign the value we will find the tan of */
    value = 0.5;
    /* Calculate the Tangent of value */
    result = tan(value);
    /* Display the result of the calculation */
    printf("The Tangent of %f is %f\n", value, result);
    return 0;

When compiled with gcc and run, this application will output:

The Tangent of 0.500000 is 0.546302

Similar Functions

Other C functions that are similar to the tan function: