If the magnitudes of a ,b and a+b are respectively 3,4 and 5 , then the magnitude of (a-b ) is

Question

Accepted Answer

Correct answer: D. (d) Given that, |a |=3 , |b |=4 and |a+b |=5 Since, |a+b |=5 ∴ |a+b |^2=25 |a |^2+2a b+ |b |^2=259+2a b+16=25a b=0 Now, consider |a-b |^2= |a |^2-2a b+ |b |^2 =9-0+16=25 ∴ |a-b |=5.

$If the magnitudes of a, b and a + b are respectively 3,4 and 5 , then the magnitude of (a - b) is$

Solution

More Vector Algebra PYQs