MATLAB Function Reference |

Secant of an argument in radians

**Syntax**

**Description**

The `sec`

function operates element-wise on arrays. The function's domains and ranges include complex values. All angles are in radians.

```
Y = sec(X)
```

returns an array the same size as `X`

containing the secant of the elements of `X`

.

**Examples**

Graph the secant over the domains and .

x1 = -pi/2+0.01:0.01:pi/2-0.01; x2 = pi/2+0.01:0.01:(3*pi/2)-0.01; plot(x1,sec(x1),x2,sec(x2)), grid on

The expression `sec(pi/2)`

does not evaluate as infinite but as the reciprocal of the floating-point accuracy `eps`

, because `pi`

is a floating-point approximation to the exact value of .

**Definition**

**Algorithm**

`sec`

uses FDLIBM, which was developed at SunSoft, a Sun Microsystems, Inc. business, by Kwok C. Ng, and others. For information about FDLIBM, see http://www.netlib.org.

**See Also**

`asec`

, `asech`

, `eps`

, `pi`

, `secd`

, `sech`

script | secd |

© 1994-2005 The MathWorks, Inc.