You may be familiar with this property of square roots:
But with imaginary numbers:
Why is this ? ?
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
The square of (-1) is 1. The square root of 1 is ±1. Since the square root of (-1) is represented by i, and it is known that i²=-1, it may be intially baffling that -1=1, but a square root always has two values, positive and negative. In this case, since -1 is also one of the roots, the equation is perfectly right!
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.