Three Dimensional Geometry Question 54
Question: If $ \alpha ,\beta , \gamma $ be the angles which a line makes with the positive direction of co-ordinate axes, then $ {{\sin }^{2}}\alpha +{{\sin }^{2}}\beta +{{\sin }^{2}}\gamma = $
[RPET 2000; AMU 2002; MP PET 1989, 98, 2000, 03, Pb. CET 2001]
Options:
A) 2
B) 1
C) 3
D) 0
Show Answer
Answer:
Correct Answer: A
Solution:
Since $ {{\cos }^{2}}\alpha +{{\cos }^{2}}\beta +{{\cos }^{2}}\gamma =1 $ $ \Rightarrow \Sigma {{\sin }^{2}}\alpha =3-1=2 $ .
BETA
