Find value of | 368/21 #vec u# + 991/21 #vec v# - 1177/21 #vec w# | ?

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1 Answer
Ananda Dasgupta
Jun 12, 2018

85

Explanation:

#367/21 vec u +991/21 vec v -1177/21 vec w#
# = 367/21(4,-1,7) +991/21(1,3,-2)-1177/21(2,2,-1)#

The three components are

  • # 1/21 (367times 4+991times 1-1177times 2) = 5 #
  • # 1/21 (367times (-1)+991times 3-1177times 2) = 12 #
  • # 1/21 (367times 7+991times (-2)-1177times (-1)) = 84 #

Hence the required answer is

#|(5,12,84)| = sqrt(5^2+12^2+84^2) = 85#

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