The root function is the inverse operation of the exponentiation.
<MATH> b^n = a </MATH>
<MATH> b = \sqrt[n]{a} = a^{\frac{1}{n}} </MATH>
If you need to get the exponent n (power), the operation is not the root function but the logarithm <MATH> n = log_b(a) </MATH>
square root is the inverse of the square operation
<MATH> y^2 = x </MATH>
<MATH> y^{\frac{1}{2}} = \sqrt[2]y = \sqrt{y} = x </MATH>
Every positive number x has two square roots:
For example: The square roots of 9 are: