Q37 / 90 · JEE Main 2022 (29 Jun Shift 2) · Mathematics

Let f be a real valued continuous function on 0, 1 and fx=x+∫01x-tftdt. Then which of the following points x, y lies on the curve y=fx?

  • A
    2, 4
  • B
    1, 2
  • C
    4, 17
  • Correct answer
    D
    6, 8

Solution

Given,

fx=x1+∫01ftdt-∫01tftdt

fx=Ax-B ...i

A=1+∫01ftdt=1+∫01At-Bdt

⇒A=21-B ...ii

Also B=∫01tftdt=∫01At2-Btdt

A=92B ...iii

From ii, iii

A=1813, B=413

So, fx=1813x-413

 ⇒f6=18×6-413=8

Hence, the correct answer is option: 'D'.

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