Three-Dimensional-Geometry Question 431

Question: If a line makes $ \alpha ,\beta ,\gamma $ with the positive direction of $ x,\ y $ and z-axis respectively. Then, $ {{\cos }^{2}}\alpha +{{\cos }^{2}}\beta +{{\cos }^{2}}\gamma $ is

[Orissa JEE 2002]

Options:

A) ½

B) ?1/2

C) ?1

D) 1

Show Answer

Answer:

Correct Answer: D

Solution:

It is obvious.