Square Roots

Opposite of applying exponents.

  • 2^{2}=4\ \Rightarrow\ \sqrt{4}=2
  • 3^{3}=27\ \Rightarrow\ \sqrt[3]{27}=3

\sqrt{\ }\ \Rightarrow\ square\ root,\ \sqrt[3]{\ }\ \Rightarrow\ cube\ root

To simplify square roots take out perfect squares.

\sqrt{4}=\sqrt{2^2}=2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \sqrt{12}=\sqrt{4\times3}=\sqrt{2^{2}\times 3}=2\sqrt{3}

 

Simplifying complex expressions:

  • Simplify: \sqrt{20x^{5}y^{7}z^{2}}
  1. Rewrite grouping perfect squares
    • \sqrt{2^{2}5x^{2}x^{2}xy^{2}y^{2}y^{2}yz^{2}
  2. Pull out perfect squares
    • 2x^{2}y^{3}z\sqrt{5xy}

Simplifying cube roots by pulling out perfect cubes:

  • Simplify: \sqrt[3]{27x^{4}y^{6}z^{2}}
  1. \sqrt[3]{3^{3}x^{3}xy^{3}y^{3}z^{2}}
  2. 3xy^{2}\sqrt[3]{xz^{2}}

Use of square roots in pythagorean theorem:

  • Triangle has legs of 5 and 12, what is the length of the hypotenuse?

a^{2}+b^{2}=c^{2}

a=5,\ b=12

5^{2}+12^{2}=c^{2}

160=c^{2}

* take square root to undo exponent

\sqrt{169}=\sqrt{c^2}

13=c