Let \(a > 0\) be a positive real number. The equation

\[x^2=a\]

has two real solutions \(x_1,x_2\in\mathbb R\), called the **square roots** of the number \(a\) and denoted by \(x_1:=\sqrt a\) and \(x_2:=- \sqrt a\).

| | | | | created: 2015-03-04 19:34:47 | modified: 2020-07-10 19:54:51 | by: *bookofproofs* | references: [581]

[581] **Forster Otto**: “Analysis 1, Differential- und Integralrechnung einer Veränderlichen”, Vieweg Studium, 1983