NAME

tan - tangent function

 SYNOPSIS

#include <math.h>

double tan(double x);

 DESCRIPTION

The tan() function computes the tangent of its argument x, measured in radians.

An application wishing to check for error situations should set errno to 0 before calling tan(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

The tan() function may lose accuracy when its argument is far from 0.0 .

 RETURN VALUE

Upon successful completion, tan() returns the tangent of x.

If x is NaN, NaN is returned and errno may be set to [EDOM].

If x is ±Inf, either 0.0 is returned and errno is set to [EDOM], or NaN is returned and errno may be set to [EDOM].

If the correct value would cause overflow, ±HUGE_VAL is returned and errno is set to [ERANGE].

If the correct value would cause underflow, 0.0 is returned and errno may be set to [ERANGE].

 ERRORS

The tan() function will fail if:

[ERANGE]

The value to be returned would cause overflow.

The tan() function may fail if:

[EDOM]

The value x is NaN or ±Inf.

[ERANGE]

The value to be returned would cause underflow.

No other errors will occur.

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

atan(), isnan(), <math.h>.

DERIVATION

Derived from Issue 1 of the SVID.