square root

[mog]

what is the square root of  -5

[stevie21]

It's been years since I did any Maths but it'll be something like 2.236i where i is the (hypothetical) square root of -1.
This is all explained better than I can if you seach online for "complex numbers"

[rojash]

As stevie21 says, the result is an "imaginary" number. Any number when multiplied by itself must result in a positive answer (negative times a negative is a positive). So there cannot be a "real" square root of a negative number. However in some practical cases it is useful to be able to pretend that there is such a thing. One example is in the calculations for crossover frequencies in loudspeakers.

[landie]

I dont think you can have a square-root of a minus value because the product of two minusses is a plus and the product of two plusses is a plus.

[Loosehead]

That's right Landie, it is called a complex number. There are 2 parts, a real part and an imaginary part. Even though you cannot have a square root of -1 (known as i) by mathmeticians and j by engineers) the complex number pair can be useful to mathmaticians and is used in a lot of pure maths.

[Nenrulez]

The answer on my calculator was -11111111x10