Question

What are direction cosines and direction ratios? Why do we need them? Explain with an example.

Answer 1

Any numbers that are proportional to the direction cosines are called direction ratios, usually represented as a, b, c. 

Answer 2

Answer:

thanks for points

The cosines of each of these angles that the line makes with the x-axis, y-axis, and z-axis respectively are called direction cosines of the line in three-dimensional geometry. ... Note that these cosines can be found only once we have found the angles that the line makes with each of the axes.