For x   ∈ R ,   x ≠ - 1 , if 1 + x 2016 + x 1 + x 2015 + x 2 1 + x 2014 + … + x…

For x R, x-1, if 1+x2016+x1+x2015+x21+x2014++x2016= i=0 2016 a i x i , then a17 is equal to
  1. 2017!17!2000!
  2. 2016!17!1999!
  3. 2016!16!
  4. 2017!2000!

Solution

S=1+x2016+x1+x2015+x21+x2014++x20151+x+x2016  ...i

x1+x S=x 1+x2015+x21+x2014++x2016+x20171+x  ...ii

ii-i

S1+x=1+x2016-x20171+x

S=1+x2017-x2017

Coefficient a17=2017C17 =2017!17!2000!

Asked in: JEE Main 2016 (09 Apr Online)

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