Verified Solution • 2025–26 Session moderate

QJEEM22Maa6c3: JEE Main 2022 Mathematics - Class 12 JEEM22Maa6c3 Solution: Let Then :

Let In(x)=∫0x1(t2+5)ndt,n=1,2,3,….I_{n}(x)=\int_{0}^{x} \frac{1}{\left(t^{2}+5\right)^{n}} d t, n=1,2,3, \ldots . Then :

Multiple Choice Options

  • A 50I6−9I5=xI5′50 I_{6}-9 I_{5}=x I_{5}^{\prime}
  • B 50I6−11I5=xI5′50 I_{6}-11 I_{5}=x I_{5}^{\prime}
  • C 50I6−9I5=I5′50 I_{6}-9 I_{5}=I_{5}^{\prime}
  • D 50I6−11I5=I5′50 I_{6}-11 I_{5}=I_{5}^{\prime}

Step-by-Step Verified Solution

In(x)=∫0x1(t2+5)ndt{I_n}(x) = \int\limits_0^x {{1 \over {{{({t^2} + 5)}^n}}}dt}

=∫0x1(t2+5)n⏟I×III dt= \int\limits_0^x {{1 \over {\underbrace {{{({t^2} + 5)}^n}}_I}} \times \mathop I\limits_{II} \,dt}

=t(t2+5)n∣0x−∫0x−2nt(t2+5)n+1×t dt= \left. {{t \over {{{({t^2} + 5)}^n}}}} \right|_0^x - \int\limits_0^x {{{ - 2nt} \over {{{({t^2} + 5)}^{n + 1}}}} \times t\,dt}

=x(x2+5)n+∫0x2n(t2+5−5(t2+5)n+1)dt= {x \over {{{({x^2} + 5)}^n}}} + \int\limits_0^x {2n\left( {{{{t^2} + 5 - 5} \over {{{({t^2} + 5)}^{n + 1}}}}} \right)dt}

In(x)=x(x2+5)n+2n In(x)−10n In+1(x){I_n}(x) = {x \over {{{({x^2} + 5)}^n}}} + 2n\,{I_n}(x) - 10n\,{I_{n + 1}}(x)

10n In+1(x)−(2n−1) In(x)=xIn′(x)10n\,{I_{n + 1}}(x) - (2n - 1)\,{I_n}(x) = xI{'_n}(x)

For n=5n = 5

50I6(x)−9I5(x)=xI5′(x)50{I_6}(x) - 9{I_5}(x) = xI{'_5}(x)

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