find two unit vectors orthogonal to both
<1, -1, 1> and <0, 4, 4>
can ya run down through this problem please.
there were square roots in the answer, i thought this was just dot product?
thanks.
o_O showed you how to do the cross product.
$\displaystyle (1,-1,1) \times (0,4,4) = (-8,-4,4)$
Now calculate the absolute value of the resulting vector:
$\displaystyle |(-8,-4,4)| = \sqrt{96}=4\sqrt{6}$
Divide the result by the absolute value to reduce the vector to the length 1:
$\displaystyle \overrightarrow{u_1} = \dfrac{(-8,-4,4)}{4\sqrt{6}} = (-2\sqrt{6}, -\sqrt{6}, \sqrt{6})$
$\displaystyle \overrightarrow{u_2} = \dfrac{(-8,-4,4)}{-4\sqrt{6}} = (2\sqrt{6}, \sqrt{6}, -\sqrt{6})$