tan-tanf-tanl.md

title	tan, tanf, tanl
description	API reference for tan, tanf, and tanl; which calculate the tangent of a floating-point value.
ms.date	1/15/2021
api_name	tan tanf tanl _o_tan _o_tanf
api_location	msvcrt.dll msvcr80.dll msvcr90.dll msvcr100.dll msvcr100_clr0400.dll msvcr110.dll msvcr110_clr0400.dll msvcr120.dll msvcr120_clr0400.dll ucrtbase.dll api-ms-win-crt-math-l1-1-0.dll
api_type	DLLExport
topic_type	apiref
f1_keywords	CORECRT_MATH/tan CORECRT_MATH/tanf CORECRT_MATH/tanl tan tanf tanl
helpviewer_keywords	tanl function tan function calculating tangents tangent tanf function trigonometric functions

tan, tanf, tanl

Calculates the tangent.

Syntax

double tan( double x );
float tanf( float x );
long double tanl( long double x );
#define tan(x) // Requires C11 or later

float tan( float x );  // C++ only
long double tan( long double x );  // C++ only

Parameters

x
Angle in radians.

Return value

The tan functions return the tangent of x. If x is greater than or equal to 263, or less than or equal to -263, a loss of significance in the result occurs.

Input	SEH exception	_matherr exception
± QNaN, IND	none	_DOMAIN
± INF	INVALID	_DOMAIN

Remarks

Because C++ allows overloading, you can call overloads of tan that take and return float or long double values. In a C program, unless you're using the <tgmath.h> macro to call this function, tan always takes and returns double.

If you use the tan macro from <tgmath.h>, the type of the argument determines which version of the function is selected. See Type-generic math for details.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	Required header (C)	Required header (C++)
tan, tanf, tanl	<math.h>	<cmath> or <math.h>
tan macro	<tgmath.h>

For more compatibility information, see Compatibility.

Example

// crt_tan.c
// This program displays the tangent of pi / 4
// Compile by using: cl crt_tan.c

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

int main( void )
{
   double pi = 3.1415926535;
   double x;

   x = tan( pi / 4 );
   printf( "tan( %f ) = %f\n", pi/4, x );
}

tan( 0.785398 ) = 1.000000

See also

Math and floating-point support
acos, acosf, acosl
asin, asinf, asinl
atan, atanf, atanl, atan2, atan2f, atan2l
cos, cosf, cosl
sin, sinf, sinl
_CItan