Let α ∈ 0 , 1 and β = log e 1 - α . Let P n x = x + x 2 2 + x 3 3 + … . + x n n ,…

Let α0,1 and β=loge1-α. Let Pnx=x+x22+x33+.+xnn,x0,1. Then the integral 0αt501-tdt is equal to
  1. β-P50α
  2. -β+P50α
  3. P50α-β
  4. β+P50α

Solution

Let

I=0αt501-tdt

I=-0α1-t50-11-tdt

I=-0α1-t501-tdt+0α11-tdt

I=-0α1+t+t2+...+t49dt-ln1-t0α

I=-t+t22+t33+...+t50500α-ln1-α

I=-α+α22+α33+...+α5050-ln1-α

I=-β+P50α

Asked in: JEE Main 2023 (31 Jan Shift 1)

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