Answer
$a_1 = 48.19°$
$a_2 = 109,47°$
$a_3 = 48.19°$
Work Step by Step
The direction angles are determined by the following formula:
$\cos {a_x} = \frac{u_x}{|u|}$ (from the book)
Given $u = <2, -1, 2>$
Thus $|u| = \sqrt{ 2^2 + (-1)^2 + (2)^2} = \sqrt{4 + 1 + 4} = \sqrt 9 = 3 $
$\cos a_1 = \frac{2}{3}$
$\cos a_2 = \frac{-1}{3}$
$\cos a_3 = \frac{2}{3}$
Solve for each angle.
$a_1 = 48.19°$
$a_2 = 109,47°$
$a_3 = 48.19°$
