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Question-59627




Question Number 59627 by naka3546 last updated on 12/May/19
Answered by tanmay last updated on 12/May/19
((3−1)/3)[(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))]  =(((b+c)/a^2 )+((c+a)/b^2 )+((a+b)/c^2 )+(1/a)+(1/b)+(1/c))−(1/3)(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))  =((b+c)/a^2 )+((c+a)/b^2 )+((a+b)/c^2 )+(1/a)+(1/b)+(1/c)−(1/3)(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))  let left hand side expression=p  right hand side exoression=q  we have to prove p−q=+ve  ot q−p=−ve  now  q=p+(1/a)+(1/b)+(1/c)−(1/3)(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))  q−p  (1/a)+(1/b)+(1/c)≥3((1/(abc)))^(1/3)   ((a+b+c)/3)≥(abc)^(1/3)   (1/a^2 )+(1/b^2 )+(1/c^2 )≥3((1/(a^2 b^2 c^2 )))^(1/3)   (a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))≥3(abc)^(1/3) ×3((1/(a^2 b^2 c^2 )))^(1/3)   so  (1/3)(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))≥3(abc)^(1/3) ×(1/((abc)^(2/3) ))  (1/3)(a+b+c)((1/a^2 )+(1/b^2 )+(1/c^2 ))≥(3/((abc)^(1/3) ))  now  3((1/(abc)))^(1/3) −(3/((abc)^(1/3) ))  =0     correction done  so p=q        ...  ....
313[(a+b+c)(1a2+1b2+1c2)]=(b+ca2+c+ab2+a+bc2+1a+1b+1c)13(a+b+c)(1a2+1b2+1c2)=b+ca2+c+ab2+a+bc2+1a+1b+1c13(a+b+c)(1a2+1b2+1c2)letlefthandsideexpression=prighthandsideexoression=qwehavetoprovepq=+veotqp=venowq=p+1a+1b+1c13(a+b+c)(1a2+1b2+1c2)qp1a+1b+1c3(1abc)13a+b+c3(abc)131a2+1b2+1c23(1a2b2c2)13(a+b+c)(1a2+1b2+1c2)3(abc)13×3(1a2b2c2)13so13(a+b+c)(1a2+1b2+1c2)3(abc)13×1(abc)2313(a+b+c)(1a2+1b2+1c2)3(abc)13now3(1abc)133(abc)13=0correctiondonesop=q.

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