Listen NCERT Audio Books - *Kitabein Ab Bolengi*

5

Find the direction cosines of the sides of the triangle whose vertices are (3, 5, –4), (-1, 1, 2) and (–5, –5, –2).

The direction cosines of the two points passing through A(x_{1}, y_{1}, z_{1}) and B(x_{2}, y_{2}, z_{2}) is given by

(x_{2} – x_{1}), (y_{2}-y_{1}), (z_{2}-z_{1})

And the direction cosines of the line AB is

Where AB =

5