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QJEEM25Mabbe6: JEE Main 2025 Mathematics - Class 11 JEEM25Mabbe6 Solution: Let . Then the value of is equal to

Let f(x)=2x+2+1622x+1+2x+4+32f(x)=\frac{2^{x+2}+16}{2^{2 x+1}+2^{x+4}+32} . Then the value of 8(f(115)+f(215)+…+f(5915))8\left(f\left(\frac{1}{15}\right)+f\left(\frac{2}{15}\right)+\ldots+f\left(\frac{59}{15}\right)\right) is equal to

Multiple Choice Options

  • A 108
  • B 92
  • C 118
  • D 102

Step-by-Step Verified Solution

amp;f(x)=42x+162.22x+16.2x+32amp;f(x)=2(2x+4)22x+8.2x+16amp;f(x)=22x+4amp;f(4−x)=2x2(2x+4)amp;f(x)+f(4−x)=12\begin{aligned}& f(x)=\frac{42^x+16}{2.2^{2 x}+16.2^x+32} \\& f(x)=\frac{2\left(2^x+4\right)}{2^{2 x}+8.2^x+16} \\& f(x)=\frac{2}{2^x+4} \\& f(4-x)=\frac{2^x}{2\left(2^x+4\right)} \\& f(x)+f(4-x)=\frac{1}{2}\end{aligned}

So, f(115)+f(5915)=12\quad \mathrm{f}\left(\frac{1}{15}\right)+\mathrm{f}\left(\frac{59}{15}\right)=\frac{1}{2}

amp; Similarly =f(2915)+f(3115)=12amp;f(3015)=f(2)=222+4=28=14amp;⇒8(29×12+14)\begin{aligned}& \text { Similarly }=f\left(\frac{29}{15}\right)+f\left(\frac{31}{15}\right)=\frac{1}{2} \\& f\left(\frac{30}{15}\right)=f(2)=\frac{2}{2^2+4}=\frac{2}{8}=\frac{1}{4} \\& \Rightarrow 8\left(29 \times \frac{1}{2}+\frac{1}{4}\right)\end{aligned}

Ans. 118

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