Expert: Socrates - 2/7/2006

Question
I'm confused
is the square root of 4 always 2? -2?
is the square root of x, x? -x also?
I'm confused
i was first introduced to
root x = plus or minus x
but then I do some questions like for solving systems, where the negative x is not the answer to root x


basically i'm confused about whether root x = + and - x .. maybe i'lil just ask my math teacher before i forget why i'm confused

Answer
The square root of a number is always positive, the square root of 4 is +2. The square root of x squared is |x|, the absolute value of x. This is to ensre that there is only one number indicated by the square root symbol. When you solve an equation like x^2 = 4 , you can say the answer is plus or minus the square root of 4, but this just means plus or minus 2. I know this is confusing, but you want the square root sign to define a function, so it can only refer to one and only one number.