Square root - one or two answers?
This accompanies a discussion of square roots by Colin Wright (@ColinTheMathmo)... [link to his blog when it's ready]
What is the definition of a square root? Are we justified in saying there's only a positive square root, or should we risk confusing students by mentioning a negative root?
This file demonstrates what happens when you take only one square root of a complex number...
It's instructive to see what it looks like when you show the other root too - just use the tick boxes.
Try dragging point A in a circle around the origin.