Plz solve

​Q48. Show that the vectors  a   , b   and   c  are coplanar, if  a   +   b   , b   + c   and   c   + a  are coplanar. 
                          Or
  Prove that, for any three vectors ​ a   , b   and   c ,​ a   +   b   b   + c     c   + a   = 2 a   b   c .

2.LHS = a + bb + cc + a=a + b . b + c×c + a=a + b . b×c + b × a + c × c + c × a=a + b .b×c + b × a +  c × a=a . b×c + a . b × a+ a . c × a + b . b×c + b . b × a+ b . c × a=abc + ab a +  ac a + bbc +  bba + bca=abc + 0 + 0+ 0 + 0 + bca=abc +  bca=abc + abc=2abc=RHSKindly ask the remaining query in different thread.

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For the 48 th question, both the first and OR question are related to each other. 
1. You have to add the first statement [a b c] = 0. then proceed as told. To prove this we write box product of all the vectors to be proven coplanar i.e. [(a+b) (b+c) (c+a)]. open this completely and write 0 whenever [a b c]  or box product with 2 same vectors appear. final answer is 0. therefore (a+b), (b+c), (c+a) is coplanar.

2. start by ​ [(a+b) (b+c) (c+a)]. open it but only substitute 0 for box product with 2 same vectors. your final result would be 2[a b c].
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What are you looking for?