# asec

## Description

example

````Y = asec(X)` returns the Inverse Secant (sec-1) of the elements of `X`. The `asec` function operates element-wise on arrays. For real elements of `X` in the interval `[-Inf,-1]` and `[1,Inf]`, `asec` returns values in the interval `[0,pi]`. For real values of `X` in the interval `[-1,1]` and for complex values of `X`, `asec` returns complex values. All angles are in radians.```

## Examples

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### Inverse Secant of a Value

`asec(-2.8)`
```ans = 1.9360```

### Inverse Secant of a Vector of Complex Values

Find the inverse secant of the elements of vector `x`. The `asec` function acts on `x` element-wise.

```x = [0.5i 1+3i -2.2+i]; Y = asec(x)```
```Y = 1.5708 + 1.4436i 1.4749 + 0.2970i 1.9503 + 0.1833i ```

### Plot the Inverse Secant Function

Plot the inverse secant function over the intervals and .

```x1 = -5:0.01:-1; x2 = 1:0.01:5; plot(x1,asec(x1),'b') hold on plot(x2,asec(x2),'b') grid on ```

## Input Arguments

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### `X` — Numeric inputnumber | vector | matrix | multidimensional array

Numeric input, specified as a number, vector, matrix, or multidimensional array.

Data Types: `single` | `double`
Complex Number Support: Yes

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### Inverse Secant

The inverse secant is defined as

${\mathrm{sec}}^{-1}\left(z\right)={\mathrm{cos}}^{-1}\left(\frac{1}{z}\right).$