Coordinate Geometry Question 88
Question: If the coordinates of vertices of $ \Delta OAB $ are (0,0) $ (\cos \alpha ,\sin \alpha ) $ and $ (-\sin \alpha ,\cos \alpha ) $ respectively, then $ OA^{2}+OB^{2}= $
Options:
A) 0
B) 1
C) 2
D) 3
Show Answer
Answer:
Correct Answer: C
Solution:
$ OA^{2}={{\cos }^{2}}\alpha +{{\sin }^{2}}\alpha =1 $ and $ OB^{2}={{\sin }^{2}}\alpha +{{\cos }^{2}}\alpha =1 $ .
Hence $ OA^{2}+OB^{2}=1+1=2 $ .
BETA
