If a line has direction ratios $2, -1, -2$, determine its direction cosines. |
$(\frac{2}{3}, -\frac{1}{3}, -\frac{2}{3})$ $(\frac{2}{3}, \frac{1}{3}, \frac{2}{3})$ $(2, -1, -2)$ $(\frac{1}{3}, -\frac{2}{3}, -\frac{2}{3})$ |
$(\frac{2}{3}, -\frac{1}{3}, -\frac{2}{3})$ |
The correct answer is Option (1) → $(\frac{2}{3}, -\frac{1}{3}, -\frac{2}{3})$ ## Direction cosines are $\frac{2}{\sqrt{2^2 + (-1)^2 + (-2)^2}}, \frac{-1}{\sqrt{2^2 + (-1)^2 + (-2)^2}}, \frac{-2}{\sqrt{2^2 + (-1)^2 + (-2)^2}}$ Or $\frac{2}{3}, -\frac{1}{3}, -\frac{2}{3}$. |