Essentials of University Mathematics
Example 3.
Find the length of the vector PQ from the point P(3.-5. 2) to the
point QC-5.4.9)
Find a unit vector with the direction of PQ


Sagot :

Answer:

The length of the vector is of [tex]\sqrt{194}[/tex]

The unit vector with the direction of PQ is [tex](\frac{8}{\sqrt{194}}, \frac{9}{\sqrt{194}}, \frac{7}{\sqrt{194}}[/tex]

Step-by-step explanation:

Vector from point P(3,-5,2) to Q(-5,4,9)

The vector is:

[tex]PQ = Q - P = (-5-3, 4-(-5), 9-2) = (8,9,7)[/tex]

The length is:

[tex]\sqrt{8^2+9^2+7^2} = \sqrt{194}[/tex]

The length of the vector is of [tex]\sqrt{194}[/tex]

Find a unit vector with the direction of PQ

We divide each component of vector PQ by its length. So

[tex](\frac{8}{\sqrt{194}}, \frac{9}{\sqrt{194}}, \frac{7}{\sqrt{194}}[/tex]

The unit vector with the direction of PQ is [tex](\frac{8}{\sqrt{194}}, \frac{9}{\sqrt{194}}, \frac{7}{\sqrt{194}}[/tex]