Definition:Square Root/Negative

Definition

Let $x \in \R_{> 0}$ be a (strictly) positive real number.

The negative square root of $x$ is the number defined and denoted as:

$-\sqrt x := y \in \R_{<0}: y^2 = x$

Also see

• Definition:Positive Square Root

Sources

• 1977: K.G. Binmore: Mathematical Analysis: A Straightforward Approach ... (previous) ... (next): $\S 1$: Real Numbers: $\S 1.10$: Quadratic equations