- #1
twoflower
- 368
- 0
The exam is behind, but I'll have to repeat it at least once :-)
Here are two problems I wasn't able to solve:
[tex]
\lim_{n \rightarrow \infty} n^2 \left[ \log \left( 1 + \frac{1}{n} \right) - \sin \left( \frac{1}{n} \right) \right]
[/tex]
I tried to solve it using Taylor, but it didn't help me...
And the second one, which I didn't even try, because I didn't catch it:
Convergence and absolute convergence of this:
[tex]
\sum_{n = 1}^{+\infty} (-1)^{n} \arctan \left( \sqrt{n^2 + 1} - \sqrt{n^2 - 1} \right)
[/tex]
How should I do that? IMO it would be sufficient that the arctan goes to 0 and then the sum would converge (Leibniz's rule)...
Thank you.
Here are two problems I wasn't able to solve:
[tex]
\lim_{n \rightarrow \infty} n^2 \left[ \log \left( 1 + \frac{1}{n} \right) - \sin \left( \frac{1}{n} \right) \right]
[/tex]
I tried to solve it using Taylor, but it didn't help me...
And the second one, which I didn't even try, because I didn't catch it:
Convergence and absolute convergence of this:
[tex]
\sum_{n = 1}^{+\infty} (-1)^{n} \arctan \left( \sqrt{n^2 + 1} - \sqrt{n^2 - 1} \right)
[/tex]
How should I do that? IMO it would be sufficient that the arctan goes to 0 and then the sum would converge (Leibniz's rule)...
Thank you.