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QJEEM24Mab69f: JEE Main 2024 Mathematics - Class 11 JEEM24Mab69f Solution: If the constant term in the expansion of , is , then is equal…

If the constant term in the expansion of (35x+2x53)12,x≠0\left(\frac{\sqrt[5]{3}}{x}+\frac{2 x}{\sqrt[3]{5}}\right)^{12}, x \neq 0 , is α×28×35\alpha \times 2^8 \times \sqrt[5]{3} , then 25α25 \alpha is equal to :

Multiple Choice Options

  • A 724
  • B 742
  • C 693
  • D 639

Step-by-Step Verified Solution

amp;(35x+2x35)12amp;Tr+1=12Cr(35x)12−r(2x53)r\begin{aligned}& \left(\frac{\sqrt[5]{3}}{x}+\frac{2 x}{\sqrt[5]{3}}\right)^{12} \\& T_{r+1}={ }^{12} C r\left(\frac{\sqrt[5]{3}}{x}\right)^{12-r}\left(\frac{2 x}{\sqrt[3]{5}}\right)^r\end{aligned}

For constant term −12+r+r=0-12+r+r=0

amp;⇒r=6amp;∴ Constant term =12C6(3)65(5)63(2)6\begin{aligned}& \Rightarrow \quad r=6 \\& \therefore \quad \text { Constant term }={ }^{12} C_6 \frac{(3)^{\frac{6}{5}}}{(5)^{\frac{6}{3}}}(2)^6\end{aligned}

amp;=12C6×2625×3.315amp;=23125×28⋅315⋅3amp;=69325⋅2835amp;∴α=69325amp;25α=693\begin{aligned}& ={ }^{12} C_6 \times \frac{2^6}{25} \times 3.3^{\frac{1}{5}} \\& =\frac{231}{25} \times 2^8 \cdot 3^{\frac{1}{5}} \cdot 3 \\& =\frac{693}{25} \cdot 2^8 \sqrt[5]{3} \\& \therefore \quad \alpha=\frac{693}{25} \\& 25 \alpha=693\end{aligned}

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