If $\omega = e^{(\frac{2\pi i}{n})}$ why $1+ \omega + \omega^{2} + ... + \omega^{n-1} = 0 $?
116360
Sum of n-th roots of unity
95145
Does $\exp(2ir\pi)$ equal $1$? What's wrong?
70974
How can zero divided by $i$ be $2\pi$?
114031
Show that $\sum_{n=0}^\infty r^n e^{i n \theta} = \frac{1- r\cos(\theta)+i r \sin(\theta)}{1+r^2-2r\cos(\theta)}$
67271
$\sum_{n=-\infty}^{\infty}\frac{1}{(u +n)^2}=\frac{\pi^2}{(\sin \pi u)^2}$
72872
Number of zeroes of solution to $y''(x)+e^{x^2}y(x)=0$ in $[0,3π]$
62913
Understanding $\sum_{n=1}^{\infty} \frac{1}{n^4} = \frac{\pi^4}{90}$
58286
Why does the $\sum_{n>1}(\zeta(n)-1)=1?$
124248
$1+\frac {1}{4}(1+\frac {1}{4}) +\frac {1}{9}(1+\frac {1}{4} +\frac {1}{9})+....$
25498
Prove that $\omega + \omega_1 = \omega \cdot \omega_1 = \omega^{\omega_1} = \omega_1$
34918
Difference between $R^\infty$ and $R^\omega$
139057
Showing that $\frac{1}{2\pi}\int^{2\pi}_{0}(2\cos\theta)^{2n}d\theta=\frac{(2n)!}{n!n!}$
113526
Why intuitively does $\mathbb E(\frac d {d\theta}\log p_\theta(x))=0$?
1869
Why does $\lim_{n\to\infty}(1+\frac{1}{n})^n = e$ instead of $1$?
143236
$ S_{n}=\frac{x}{x+1}+\frac{x^2}{(x+1)(x^2+1)}+...........+\frac{x^{2^{n}}}{(x+1)(x^2+1)...(x^{2^{n}}+1)}$
100608
Prove that $\|v\|_{H^1(\Omega )}\leq C(\|f\|_{L^2(\Omega )}+\|v\|_{H^{1/2}(\partial \Omega )}+\|\partial _\nu v\|_{H^{1/2}(\partial \Omega )}))$
67350
Analytic solution of: ${u}''+\frac{1}{x}{u}'=-\delta e^{u}$