If -2, 2, 1 are direction ratios of a line, then its direction cosiness are:

The direction cosines of the given line are given by

$\pm \frac{-2}{\sqrt{(-2{)}^2+2^2+1^2}},\pm \frac{2}{\sqrt{(-2{)}^2+2^2+1^2}},\pm \frac{1}{\sqrt{(-2{)}^2+2^2+1^2}}$

$\Rightarrow$The require direction cosines are $-\frac{2}{3},\frac{2}{2},\frac{1}{3}$

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