If |a| , , = 3, , , ,|b| , , = 4 and |a + b| , , = 5, then |a - b… - Vidyadip

MCQ

If $|a|\,\, = 3,\,\,\,|b|\,\, = 4$ and $|a + b|\,\, = 5,$ then $|a - b|\,\, = $

A
$6$
✓
$5$
C
$4$
D
$3$

✓

Answer

Correct option: B.

$5$

b
(b) We have $|a + b{|^2} + |a - b{|^2} = 2(|a{|^2} + |b{|^2})$

$\therefore \,\,\,25 + |a - b{|^2} = 2(9 + 16) \Rightarrow |a - b| = 5$.

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