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Square root

`B = sqrt(`

returns
the square root of each element of the array `X`

)`X`

.
For the elements of `X`

that are negative or complex, `sqrt(X)`

produces
complex results.

The `sqrt`

function’s domain includes
negative and complex numbers, which can lead to unexpected results
if used unintentionally. For negative and complex numbers ```
z
= u + i*w
```

, the complex square root `sqrt(z)`

returns

`sqrt(r)*(cos(phi/2) + 1i*sin(phi/2))`

where `r = abs(z)`

is the radius and ```
phi
= angle(z)
```

is the phase angle on the closed interval ```
-pi
<= phi <= pi
```

.

If you want negative and complex numbers to return error messages
rather than return complex results, use `realsqrt`

instead.

See

`sqrtm`

for the matrix square root.