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MHT CET202122 Sep 2021Morning ShiftMathematicsThree Dimensional GeometryActual

If | u |=2 and u makes angles of 60^ and 120^ with axes OX and OY in the origin, then u =

Options

  1. Ai + j + 2 k
  2. B2( i + j 2 k )
  3. C2( i - j + 2 k )
  4. D2( i - j 2 k )

Correct answer

D. 2( i - j 2 k )

Step-by-step solution

We have | u |=2 and =60^ = 1 2 and = 120^ =- 1 2 Now ^2 =1- ( 1 4 + 1 4 )= 1 2 = 1 2 Thus direction of u are 1,-1, 2 u =2( i - j 2 k )

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