KCET2018MathematicsVector Algebra
If ( | a b |²+| a b |²=144 ) and ( | a |=4 ), then the value of ( | b | ) is
Options
- A( 11 )
- B( 12 )
- C( 03 )
- D( 04 )
Correct answer
C. ( 03 )
Step-by-step solution
Given that, | a b |²+| a b |²=144 and | a |=4 We know, | a b |²+| a b |²=| a |² | b |² ² +| a |² | b |² ² =| a |² | b |² ( ² + ² )=| a |²| b |² | a b |²+| a b |²=| a |²| b |² So, (144)=16| b |² 9=| b |² | b |=3