MA0001/Exercise 5/tasks/2.tex

22 lines
893 B
TeX
Raw Normal View History

2020-09-27 11:29:20 +02:00
\begin{align*}
\lim_{n\to\infty} a_n &= \lim_{n\to\infty} \frac{\sqrt{n^2+6n+9}}{\sqrt{n^2+1}} \\[1ex]
\lim_{n\to\infty} a_n &= \lim_{n\to\infty} \sqrt{\frac{n^2+6n+9}{n^2+1}} \\
\end{align*}
Ettersom $\lim\limits_{n\to\infty} (a_n b_n) = (\lim\limits_{n\to\infty} a_n)(\lim\limits_{n\to\infty}b_n)$
\[\lim_{n\to\infty} a_n = \sqrt{ \lim_{n\to\infty} \frac{n^2+6n+9}{n^2+1}} \]
Ettersom $\lim\limits_{n\to\infty} \frac{a_n}{b_n}= \frac{\lim\limits_{n\to\infty} a_n}{\lim\limits_{n\to\infty}b_n}$ \\
I tillegg deler vi både teller og nevner på $n^2$
\[ \lim_{n\to\infty} a_n = \sqrt{ \frac{ \lim_{n\to\infty} 1+\frac{6}{n}+\frac{9}{n^2}}{ \lim_{n\to\infty} 1+\frac{1}{n^2}}} \]
Både $\frac{9}{n^2}$, $\frac{6}{n}$ og $\frac{1}{n^2}$ går mot $0$ når $n \to \infty$
\begin{align*}
\lim_{n\to\infty} a_n &= \sqrt{ \frac{ 1+0+0}{ 0+1}} \\
&= \sqrt{1} \\
&= 1 \\
\end{align*}