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QJEEM25Ma9c6e: JEE Main 2025 Mathematics - Class 12 JEEM25Ma9c6e Solution: If , then is

If I(m, n)=\int_0^1 x^{m-1}(1-x)^{n-1} d x, m, n>0 , then I(9,14)+I(10,13)I(9,14)+I(10,13) is

Multiple Choice Options

  • A I(9,1)I(9,1)
  • B I(1,13)I(1,13)
  • C I(19,27)\mathrm{I}(19,27)
  • D I(9,13)\mathrm{I}(9,13)

Step-by-Step Verified Solution

amp;I( m, m)=∫01xm−1(1−x)n−1dxamp; Let x=sin⁡2θdx=2sin⁡θcos⁡θ dθamp;I( m,n)=2∫0π/2(sin⁡θ)2 m−1(cos⁡θ)2n−1 dθamp;I(9,14)+I(10,13)=2∫0π/2(sin⁡θ)17(cos⁡θ)27 dθamp;+2∫0π/2(sin⁡θ)19(cos⁡θ)25 dθamp;=2∫0π/2(sin⁡θ)17(cos⁡θ)25 dθamp;=I(9,13)\begin{aligned}& \mathrm{I}(\mathrm{~m}, \mathrm{~m})=\int_0^1 \mathrm{x}^{\mathrm{m}-1}(1-\mathrm{x})^{\mathrm{n}-1} \mathrm{dx} \\& \text { Let } \mathrm{x}=\sin ^2 \theta \quad \mathrm{dx}=2 \sin \theta \cos \theta \mathrm{~d} \theta \\& \mathrm{I}(\mathrm{~m}, \mathrm{n})=2 \int_0^{\pi / 2}(\sin \theta)^{2 \mathrm{~m}-1}(\cos \theta)^{2 \mathrm{n}-1} \mathrm{~d} \theta \\& \mathrm{I}(9,14)+\mathrm{I}(10,13)=2 \int_0^{\pi / 2}(\sin \theta)^{17}(\cos \theta)^{27} \mathrm{~d} \theta \\& +2 \int_0^{\pi / 2}(\sin \theta)^{19}(\cos \theta)^{25} \mathrm{~d} \theta \\& =2 \int_0^{\pi / 2}(\sin \theta)^{17}(\cos \theta)^{25} \mathrm{~d} \theta \\& =\mathrm{I}(9,13)\end{aligned}

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