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Manipal MET2011MathematicsVector Algebra

Let a , b , c , be three vectors such that c 0 and a b =2 a c ,| a |=| c |=1,| b |=4 and |b c|= 15 , if b-2 c= . then, equals

Options

  1. A-1
  2. B1
  3. C-4
  4. D2

Correct answer

C. -4

Step-by-step solution

Let angle between b and c is , then | b c |= 15 (given) aligned & |b||c| = 15 & = 15 4 aligned = 1 4 Also, b -2 c = a array ll & (b-2 c)^2= ^2(a)^2 & |b|^2+4|c|^2-4 b c= ^2|a|^2 & 16+4-4 |b||c| = ^2 & ^2=16 & = 4 array

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