Comment 4 for bug 656575

Please see: Help|LibreOffice Help|Index|SQRT function:
<quote>
SQRT
Returns the positive square root of a number.
Syntax
SQRT(Number)
Returns the positive square root of Number.
Number must be positive.
Example
=SQRT(16) returns 4.
=SQRT(-16) returns an invalid argument error.
</quote>

if you wish to find the square root of a complex number use IMSQRT.
From Help:
<quote>
IMSQRT
The result is the square root of a complex number.
Syntax
IMSQRT("ComplexNumber")
ComplexNumber is a complex number that is entered in the form "x+yi" or "x+yj".
Example
=IMSQRT("3+4i") returns 2+1i.
</quote>

And testing in LibreOffice 3.3.1-1ubuntu4:
=IMSQRT(-1)
results in: i
IMSQRT(-16):
results in: 4i

$ apt-cache policy libreoffice
libreoffice:
  Installed: 1:3.3.1-1ubuntu4
  Candidate: 1:3.3.1-1ubuntu4
  Version table:
 *** 1:3.3.1-1ubuntu4 0
        500 http://archive.ubuntu.com/ubuntu/ natty/main amd64 Packages
        100 /var/lib/dpkg/status