Mathematics
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qifeng618
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About

I am a Chinese mathematician. My full name in English is Feng Qi. For more information on me, please visit the following sites:

https://research.com/u/feng-qi

https://qifeng618.wordpress.com

https://www.researchgate.net/profile/Feng_Qi

https://orcid.org/0000-0001-6239-2968

https://scholar.google.com/citations?user=Q-wGSBYAAAAJ

https://www.webofscience.com/wos/author/record/G-2455-2012

https://www.growkudos.com/profile/feng_qi

https://www.semanticscholar.org/author/Feng-Qi/143785202

http://www.scopus.com/authid/detail.url?authorId=7101777278

http://www.ams.org/mathscinet/search/author.html?mrauthid=610520

https://zbmath.org/authors/?q=ai:qi.feng

Welcome your visits.

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All Questions Answers
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question
7
What is the general formula of the sum $\sum_{k=0}^{n}(-1)^{k} \binom{n}{k}\binom{k/2}{m}$ for $m,n\in\mathbb{N}$?
Aug 28, 2021
answer
6
Can we prove AM-GM Inequality using these integrals?
Sep 21, 2021
question
5
Ask for a proof of logarithmically complete monotonicity of a power-exponential function involving the difference of the psi and logarithmic functions
Sep 20, 2021
question
3
Is the reciprocal of the inverse tangent function, $\frac1{\arctan x}$, a (logarithmically) completely monotonic function on $(0,\infty)$?
Sep 10, 2021
answer
3
Compact formula for the $n^\text{th}$ derivative of $\operatorname{sech}^2(x)$?
Sep 13, 2021
answer
3
Asymptotic Expansion of Digamma Function
Sep 26, 2021
answer
3
$n$th derivative of $e^{ax^m}$
Mar 11
answer
3
Is there a closed form formula for the Bernoulli numbers?
Sep 22, 2021
answer
3
Prove that $\sin n\theta=n\sin \theta-\frac{n(n^2-1)}{3!}\sin^3\theta+\frac{n(n^2-1)(n^2-3^2)}{5!}\sin^5\theta+\cdots$
Feb 12, 2022
answer
3
Integrating $\int_a^b\left[ \left(1 - \frac{a}{x} \right)\left(\frac{b}{x}-1 \right) \right]^\frac{1}{2}dx$
Sep 21, 2021
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7
Is the Gauss hypergeometric series ${}_2F_1\bigl(\frac{1}{2},\frac{1}{2};2;t\bigr)$ an elementary function?
5
How to prove the combinatorial identity $\sum_{k=\ell}^{n}\binom{2n-k-1}{n-1}k2^k=2^\ell n\binom{2n-\ell}{n}$ for $n\ge\ell\ge0$?

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