Verified Solution • 2025–26 Session moderate

QJEEM02Maf941: JEE Main 2002 Mathematics - Class 12 JEEM02Maf941 Solution

lim⁡x→∞(x2+5x+3x2+x+2)x\mathop {\lim }\limits_{x \to \infty } {\left( {{{{x^2} + 5x + 3} \over {{x^2} + x + 2}}} \right)^x}

Multiple Choice Options

  • A e4{e^4}
  • B e2{e^2}
  • C e3{e^3}
  • D 11

Step-by-Step Verified Solution

lim⁡x→∞(x2+5x+3x2+x+2)x\mathop {\lim }\limits_{x \to \infty } {\left( {{{{x^2} + 5x + 3} \over {{x^2} + x + 2}}} \right)^x}

=lim⁡x→∞(1+4x+1x2+x+2)x= \mathop {\lim }\limits_{x \to \infty } {\left( {1 + {{4x + 1} \over {{x^2} + x + 2 }}} \right)^x}

=lim⁡x→∞[(1+4x+1x2+x+2)x2+x+24x+1](4x+1)xx2+x+2= \mathop {\lim }\limits_{x \to \infty } {\left[ {{{\left( {1 + {{4x + 1} \over {{x^2} + x + 2}}} \right)}^{{{{x^2} + x + 2} \over {4x + 1}}}}} \right]^{{{\left( {4x + 1} \right)x} \over {{x^2} + x + 2}}}}

= lim⁡x→∞[(1+4x+1x2+x+2)14x+1x2+x+2](4x+1)xx2+x+2\mathop {\lim }\limits_{x \to \infty } {\left[ {{{\left( {1 + {{4x + 1} \over {{x^2} + x + 2}}} \right)}^{{1 \over {{{4x + 1} \over {{x^2} + x + 2}}}}}}} \right]^{{{\left( {4x + 1} \right)x} \over {{x^2} + x + 2}}}}

=elim⁡x→∞4x2+xx2+x+2= {e^{\mathop {\lim }\limits_{x \to \infty } {{4{x^2} + x} \over {{x^2} + x + 2}}}}

[ As lim⁡x→∞(1+λx)1x=eλ\mathop {\lim }\limits_{x \to \infty } {\left( {1 + \lambda x} \right)^{{1 \over x}}} = {e^\lambda } ]

=elim⁡x→∞4+1x1+1x+2x2=e4= {e^{\mathop {\lim }\limits_{x \to \infty } {{4 + {1 \over x}} \over {1 + {1 \over x} + {2 \over {{x^2}}}}}}} = {e^4}

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