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Lim n-> infinite (5n^2+7n/4n^2-4)^n

User Topalkata
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1 Answer

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\displaystyle\lim_(n\to\infty)\left((5n^2+7n)/(4n^2-4)\right)^n=\lim_(n\to\infty)\exp\left(n\ln(5n^2+7n)/(4n^2-4)\right)=\exp\left(\lim_(n\to\infty)n\ln(5n^2+7n)/(4n^2-4)\right)


(5n^2+7n)/(4n^2-4)=\frac54+\frac3{2n+2}+\frac1{4n-4}

As
n\to\infty, the above expression approaches
\frac54. Meanwhile
n\ln(5n^2+7n)/(4n^2-4)\to\infty*\ln\left(\frac54\right)=\infty.

So,


\displaystyle\lim_(n\to\infty)\left((5n^2+7n)/(4n^2-4)\right)^n=\infty
User Toufic Batache
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