Three Dimensional Geometry — Class 12 Maths Solution

Direction cosines of $(2\widehat {\rm{i}} + 2\widehat {\rm{j}} - \widehat {\rm{k}})$ are $\frac{2}{{\sqrt {4 + 4 + 1} }},$ $\frac{2}{{\sqrt {4 + 4 + 1} }},$ $\frac{{ - 1}}{{\sqrt {4 + 4 + 1} }}$ i.e.,

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