Vectors Question 125

Question: If for two vector $ \overrightarrow{A} $ and $ \overrightarrow{B} $ , sum $ (\overrightarrow{A}+\overrightarrow{B}) $ is perpendicular to the difference $ (\overrightarrow{A}-\overrightarrow{B}) $ . The ratio of their magnitude is

Options:

A) 1

B) 2

C) 3

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ (\overrightarrow{A}+\overrightarrow{B}) $ is perpendicular to $ (\overrightarrow{A}-\overrightarrow{B}) $ . Thus $ (\overrightarrow{A}+\overrightarrow{B}) $ . $ (\overrightarrow{A}-\overrightarrow{B}) $ = 0 or $ A^{2}+\overrightarrow{B},.,\overrightarrow{A}-\overrightarrow{A},.,\overrightarrow{B}-B^{2}=0, $ Because of commutative property of dot product $ \overrightarrow{A}.\overrightarrow{B}=\overrightarrow{B}.\overrightarrow{A} $
$ \

Therefore $ $ A^{2}-B^{2}=0 $ or $ A=B $ Thus the ratio of magnitudes A/B = 1