Copyright © 1997 The Open Group

tan - tangent function

`#include <math.h> double tan(double`

x);

Thetan()function computes the tangent of its argumentx, measured in radians.An application wishing to check for error situations should set

errnoto 0 before callingtan(). Iferrnois 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 .

Upon successful completion,tan()returns the tangent ofx.If

xis NaN, NaN is returned anderrnomay be set to [EDOM].If

xis ±Inf, either 0.0 is returned anderrnois set to [EDOM], or NaN is returned anderrnomay be set to [EDOM].If the correct value would cause overflow, ±HUGE_VAL is returned and

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

errnomay be set to [ERANGE].

Thetan()function will fail if:

- [ERANGE]
- The value to be returned would cause overflow.
The

tan()function may fail if:

- [EDOM]
- The value
xis NaN or ±Inf.- [ERANGE]
- The value to be returned would cause underflow.
No other errors will occur.

None.

None.

None.

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

Derived from Issue 1 of the SVID.

Copyright © 1997 The Open Group

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