Mathematics

Problem

A line passes through the points

(6, -7, -1)

and

(2, -3, 1)

. The direction cosines of the line so directed that the angle made by it with the positive direction of

x

-axis is acute, are a.

\frac{2}{3}, -\frac{2}{3}, -\frac{1}{3}

-\frac{2}{3}, \frac{2}{3}, \frac{1}{3}

\frac{2}{3}, -\frac{2}{3}, \frac{1}{3}

\frac{2}{3}, \frac{2}{3}, \frac{1}{3}