Lucian
Reputation
93/100 score
1 26 77
Impact
~316k people reached

 72 What function can be differentiated twice, but not 3 times? 43 How can I write the numbers 5 and 7 as some sequence of operations on three 9s? 41 Why is a rectangle a parallelogram, but a parallelogram is not a rectangle? 41 I found this odd relationship, $x^2 = \sum_{k = 0}^{x-1} (2k + 1)$. 33 Mathematicians ahead of their time?

### Reputation (26,446)

 +10 Proving $\int_{0}^{\infty} \mathrm{e}^{-x^2} dx = \dfrac{\sqrt \pi}{2}$ +15 Let $x$ be an integer and $n$ be a positive integer. Find the smallest $n$ such that $x^4+n^2$ is not a prime for any $x$. +15 Integral of $\cosh^3(x)$ +10 Write 100 as the sum of two positive integers

### Questions (9)

 22 Closed Form for the Imaginary Part of $\text{Li}_3\Big(\frac{1+i}2\Big)$ 13 Evaluating $\int_0^{2\pi}\frac{dt}{\sqrt[4]{P(\cos t,\sin t)}}$ 13 Irreducibility of $~\frac{x^{6k+2}-x+1}{x^2-x+1}~$ over $\mathbb Q[x]$ 12 Proving that $\int_0^\infty\Big(\sqrt[n]{1+x^n}-x\Big)dx~=~\frac12\cdot{-1/n\choose+1/n}^{-1}$ 8 Superelliptic Area Of $x^5+y^5=r^5$

### Tags (246)

 648 calculus × 304 160 limits × 89 470 integration × 271 155 complex-analysis × 45 249 sequences-and-series × 134 152 algebra-precalculus × 74 244 real-analysis × 90 141 summation × 56 222 definite-integrals × 126 136 soft-question × 50

### Accounts (4)

 Mathematics 26,446 rep 12677 Mathematics Educators 357 rep 14 MathOverflow 224 rep 1312 Linguistics 159 rep 14