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# 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

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