Vector Magnitude and Direction Math Example 2

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Example 2

medium
Find the unit vector in the direction of v=1,2,2\mathbf{v} = \langle 1, 2, 2 \rangle.

Solution

  1. 1
    Step 1: v=1+4+4=9=3\|\mathbf{v}\| = \sqrt{1 + 4 + 4} = \sqrt{9} = 3.
  2. 2
    Step 2: v^=vv=131,2,2=13,23,23\hat{\mathbf{v}} = \frac{\mathbf{v}}{\|\mathbf{v}\|} = \frac{1}{3}\langle 1, 2, 2 \rangle = \langle \frac{1}{3}, \frac{2}{3}, \frac{2}{3} \rangle.
  3. 3
    Check: v^=1/9+4/9+4/9=9/9=1\|\hat{\mathbf{v}}\| = \sqrt{1/9 + 4/9 + 4/9} = \sqrt{9/9} = 1

Answer

13,23,23\langle \frac{1}{3}, \frac{2}{3}, \frac{2}{3} \rangle
A unit vector has magnitude 1 and preserves the direction of the original vector. Divide each component by the magnitude to normalize.

About Vector Magnitude and Direction

The magnitude v\|\mathbf{v}\| is a vector's length; the direction is the angle it makes with a reference axis.

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