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AP EAMCET202018 Sep 2020Morning ShiftMathematicsVector AlgebraActual

Let ( u , v ) and ( w ) be three vectors such that ( u + v + w =0,| u |=3,| v |=5 ) and (| w |=7 ). Then the angle between ( u ) and ( v ) is

Options

  1. A(60^ )
  2. B(70^ )
  3. C(80^ )
  4. D(90^ )

Correct answer

A. (60^ )

Step-by-step solution

Given that, (| u |=3,| v |=5 ) and (|w|=7 ) and ( u + v + w =0 u + v =- w ) ( aligned & | u |^2+| v |^2+2 u . v =| w |^2 & 9+25+2 3 5 =49, aligned ) if angle between ( u ) and ( v ) is ( ) ( = 1 2 =60^ )

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