ziang chen

### Questions (94)

 54 How to solve fifth-degree equations by elliptic functions? 32 An inequality: $1+\frac1{2^2}+\frac1{3^2}+\dotsb+\frac1{n^2}\lt\frac53$ 22 The series $\sum\limits_{n=1}^\infty \frac n{\frac1{a_1}+\frac1{a_2}+\dotsb+\frac1{a_n}}$ is convergent 19 Sum of irrational numbers, a basic algebra problem 18 $\int_0^1f(x)dx=1, \int_0^1xf(x)dx=\frac16$ minimum value of $\int_0^1f^2(x) dx$?

### Reputation (4,271)

This user has no recent positive reputation changes

 7 Prove that if $(ab)^2 = e$, then $(ba)^2 = e$ 7 Prove $(1-\cos x)/\sin x = \tan x/2$ 6 Convergence of $\sum \frac{\sqrt{a_n}}{n^p}$ 5 Showing that $f(x)=e^{-x}$ is uniformly continuous on $[0,\infty)$ 5 Why does $\lim\limits_{t\to-\infty}te^t=0$?

### Tags (80)

 45 calculus × 38 11 convergence × 4 32 limits × 14 9 group-theory × 4 29 real-analysis × 31 8 abstract-algebra × 8 25 sequences-and-series × 13 7 analysis × 15 11 trigonometry × 5 5 inequality × 15

### Account (1)

 Mathematics 4,271 rep 1647