Trắc nghiệm:
$1. C$
$2. D$
$3. B$
$4. C$
$5. A$
$6. A$
$7. A$
$8. C$
$9. A$
$10. A$
Tự luận:
a,
$\lim(\sqrt{n^2-n}-n)$
$=\lim\dfrac{n^2-n-n^2}{\sqrt{n^2-n}+n}$
$=\lim\dfrac{-n}{\sqrt{n^2-n}+n}$
$=\lim\dfrac{-1}{\sqrt{1-\dfrac{1}{n}}+1}$
$=\dfrac{-1}{2}$
b,
$\lim\dfrac{3^n+5^n.5}{4^n-2.5^n}$
$=\lim\dfrac{0,6^n+5}{0,8^n-2}$
$=\dfrac{-5}{2}$
