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AP EAMCET2005MathematicsVector Algebra

If a and b are unit vectors, then the vector ( a + b ) ( a b ) is parallel to the vector

Options

  1. Aa - b
  2. Ba + b
  3. C2 a - b
  4. D2 a + b

Correct answer

B. a + b

Step-by-step solution

Now, ( a + b ) ( a b ) aligned & a ( a b )+ b ( a b ) & =( a b ) a -( a a ) b +( b b ) a -( b a ) b & [ a and b are unit vectors a . a = b . b =1] & =( a b ) a - b + a -( b a ) b & =( a b )( a - b )+ a - b & =( a - b )( a b -1) & aligned Given vector is parallel to ( a - b ) .

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