brechtjah 16 Junior Poster in Training

Yes installing the Microsoft Core Fonts did the job. Here's a quick how to for other people that may be experiencing this in Ubuntu 8.10.
Non-Terminal:
Go to Applications > Add/Remove...
and Search for microsoft core fonts (make sure All Available Applications is selected next to the search box)
Check the box and click Apply Changes

Terminal:
Open the Terminal: Applications > Accessories > Terminal
Type in: sudo apt-get install msttcorefonts
After this you will be prompted your password and the installing will begin.

After installing the fonts you will have to logout for them to be applied.

Nick Evan commented: Thanks for the Ubuntu tip! +15
brechtjah 16 Junior Poster in Training

* -1
The square root of -1 is -1 we say. So it would just make your number negative.
Maybe this documentation is helpful for you too :)
http://en.wikipedia.org/wiki/Complex_number

ohnomis commented: help with complex numbers +1