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→Two square roots for each number: putting +/- notation back in, discuss on talk before reverting, please.
All numbers have two square roots, although they don't have to be distinct. For example, the square root of zero has two values: +0 and -0.
All numbers have two square roots, although they don't have to be distinct. For example, the square root of zero has two values: +0 and -0.
As such, the technically correct way of writing is
:<math>\sqrt{9} = \pm 3</math>
This has important implications when solving equations, in that, if the square root of both sides is taken, one must be careful to allow for both the positive and negative square root. A well known example is [[completing the square]] to solve a [[quadratic equation]].
This has important implications when solving equations, in that, if the square root of both sides is taken, one must be careful to allow for both the positive and negative square root. A well known example is [[completing the square]] to solve a [[quadratic equation]].