Evaluate limn→∞∑k=1nnn2+4k2\lim_{n \to \infty} \sum_{k=1}^n \frac{n}{n^2 + 4k^2}limn→∞∑k=1nn2+4k2n.
12arctan(2)\frac{1}{2}\arctan(2)21arctan(2)
π4\frac{\pi}{4}4π
14arctan(2)\frac{1}{4}\arctan(2)41arctan(2)
ln2\ln 2ln2