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QJEEM24Ma7533: JEE Main 2024 Mathematics - Class 11 JEEM24Ma7533 Solution: If and , then the point lies on the line

If 11+2+12+3+…+199+100=m\frac{1}{\sqrt{1}+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+\ldots+\frac{1}{\sqrt{99}+\sqrt{100}}=m and 11⋅2+12⋅3+…+199⋅100=n\frac{1}{1 \cdot 2}+\frac{1}{2 \cdot 3}+\ldots+\frac{1}{99 \cdot 100}=\mathrm{n} , then the point (m,n)(\mathrm{m}, \mathrm{n}) lies on the line

Multiple Choice Options

  • A 11(x−1)−100y=011(x-1)-100 y=0
  • B 11x−100y=011 x-100 y=0
  • C 11(x−1)−100(y−2)=011(x-1)-100(y-2)=0
  • D 11(x−2)−100(y−1)=011(x-2)-100(y-1)=0

Step-by-Step Verified Solution

amp;11+2+12+3+…+199+100=mamp; and 11⋅2+12⋅3+…+199⋅100=namp;11+2+12+3+…+199+100amp;=11+2×2−12−1+13+2×3−23−2amp;+…+199+100×100−99100−99\begin{aligned}& \frac{1}{\sqrt{1}+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+\ldots+\frac{1}{\sqrt{99}+\sqrt{100}}=m \\& \text { and } \frac{1}{1 \cdot 2}+\frac{1}{2 \cdot 3}+\ldots+\frac{1}{99 \cdot 100}=n \\& \frac{1}{\sqrt{1}+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+\ldots+\frac{1}{\sqrt{99}+\sqrt{100}} \\& =\frac{1}{\sqrt{1}+\sqrt{2}} \times \frac{\sqrt{2}-\sqrt{1}}{\sqrt{2}-\sqrt{1}}+\frac{1}{\sqrt{3}+\sqrt{2}} \times \frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}-\sqrt{2}} \\& \quad+\ldots+\frac{1}{\sqrt{99}+\sqrt{100}} \times \frac{\sqrt{100}-\sqrt{99}}{\sqrt{100}-\sqrt{99}}\end{aligned}

amp;=2−1+3−2+…+100−99amp;=100−1amp;=10−1amp;⇒m=9\begin{aligned}& =\sqrt{2}-\sqrt{1}+\sqrt{3}-\sqrt{2}+\ldots+\sqrt{100}-\sqrt{99} \\& =\sqrt{100}-\sqrt{1} \\& =10-1 \\& \Rightarrow m=9\end{aligned}

and 11⋅2+12⋅3+…+199⋅100=n\frac{1}{1 \cdot 2}+\frac{1}{2 \cdot 3}+\ldots+\frac{1}{99 \cdot 100}=n

amp;2−11×2+3−22×3+…+100−99100×99=namp;⇒1−12+12−13+…+199−1100=namp;⇒n=1−1100amp;⇒n=99100amp;(m,n)=(9,99100)\begin{aligned}& \frac{2-1}{1 \times 2}+\frac{3-2}{2 \times 3}+\ldots+\frac{100-99}{100 \times 99}=n \\& \Rightarrow 1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\ldots+\frac{1}{99}-\frac{1}{100}=n \\& \Rightarrow n=1-\frac{1}{100} \\& \Rightarrow n=\frac{99}{100} \\& (m, n)=\left(9, \frac{99}{100}\right)\end{aligned}

Satisfies the line 11x−100y=011 x-100 y=0

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