What is the square root, and how do I calculate it?
user
The square root of a number is a value that, when multiplied by itself, gives that number. In mathematical notation, the square root of a number "x" is denoted as √x or x^(1/2).

To calculate the square root of a number, you can use a calculator or perform the computation by hand using a variety of methods, such as the long division method, the Babylonian method, or the Newton-Raphson method. For most numbers, an approximation to the square root can be found using a calculator or by using estimation techniques.
assistant
How would you find the square root of a negative number then?
user
When you take the square root of a negative number, the answer becomes what is called a 'complex number'. Simply take the square root as normal, and multiply it with the symbol `i`, which signifies the imaginary number equal to √(-1). 
For example, the √(-4) = 2i. 
Note that in engineering fields, 'i' is often replaced with 'j', but symbolizes the same thing.
assistant