Determine when whether the sequence converges or diverges. If it converges, find the limit$.a_n=\frac{4n^2-3n}{2n1}$

$a_n=\frac{n^4}{n^3-2n}$

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$a_n=2(0\mathrm{.}86{)}^n$

$a_n=3^n{7}^{-n}$

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