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MHT CET202121 Sep 2021Morning ShiftMathematicsVector AlgebraActual

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

Options

  1. A9
  2. B25
  3. C5
  4. D4

Correct answer

C. 5

Step-by-step solution

aligned & | a + b |^2=| a - b |^2+4 a b & Now | a - b |^2=| a |^2+| b |^2-2 a b & (5)^2=(3)^2+(4)^2-2 a b a b =0 aligned Substituting in (1), we get | a + b |^2=| a - b |^2 | a + b |=5

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