Consider the integral I = ∫ 0 10 x e x e x - 1 d x where x denotes the greatest integer less than or…

Consider the integral I=010xexex-1dx where x denotes the greatest integer less than or equal to x. Then the value of I is equal to :

  1. 9e-1
  2. 45e+1
  3. 45e-1
  4. 9e+1

Solution

I=010x·ex-x+1

I=010dx+121·e2-x+232·e3-x+..+9109·e10-xdx

I=n=09nn+1n·en+1-xdx

=-n=09nen+1-xnn+1

=-n=09n·e0-e1

=e-1n=09n

=e-1·9·102

=45e-1

Asked in: JEE Main 2021 (16 Mar Shift 2)

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