Equations - Square Root

Square Root

Definition and Properties

The square root of a number is a value that, when multiplied by itself, gives the original number. It is denoted by the radical symbol \( \sqrt{} \). For example, \( \sqrt{9} = 3 \) because \( 3 \times 3 = 9 \).

Graphical explanation of square root

Key Properties

  • \( \sqrt{a^2} = |a| \), for any real number \( a \)
  • \( \sqrt{ab} = \sqrt{a} \cdot \sqrt{b} \), for non-negative \( a \) and \( b \)
  • \( \sqrt{\frac{a}{b}} = \frac{\sqrt{a}}{\sqrt{b}} \), where \( b \neq 0 \)
  • The square root of a negative number is not a real number (e.g., \( \sqrt{-1} = i \), the imaginary unit)

Applications

  • Used in geometry to calculate lengths using the Pythagorean theorem.
  • Appears in solving quadratic equations and algebraic simplifications.
  • Common in science and engineering for modeling areas, speeds, and signal strengths.
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