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ccorn's user avatar
ccorn's user avatar
ccorn
  • Member for 12 years, 7 months
  • Last seen this week
33 votes
Accepted

How prove this $\sum_{k=1}^{2^{n-1}}\sigma{(2^n-2k+1)}\sigma{(2k-1)}=8^{n-1}$

30 votes

Galois group of $x^4-5$

22 votes
Accepted

Coefficient of $n$th cyclotomic polynomial equals $-\mu(n)$

22 votes

Is there a good way to compute Christoffel Symbols

15 votes

I found this odd relationship, $x^2 = \sum_\limits{k = 0}^{x-1} (2k + 1)$.

15 votes

Binomial Identity $\sum\binom{2n+1}{2k+1}\binom{m+k}{2n} = \binom{2m}{2n}$

15 votes
Accepted

Generalizing the sum of consecutive cubes $\sum_{k=1}^n k^3 = \Big(\sum_{k=1}^n k\Big)^2$ to other odd powers

15 votes

Common Math Mistakes Made by Scientists

14 votes
Accepted

Ramanujan's tau function identity

14 votes

What is the norm function in $\mathcal{O}_{\mathbb{Q}(\zeta_8)}$?

13 votes
Accepted

How to prove that trace$(ABA^{-1}B^{-1})$=$3$

13 votes
Accepted

How to prove that $\frac{\eta^{14}(q^4)}{\eta^{4}(q^8)}=4\eta^4(q^2)\eta^2(q^4)\eta^4(q^8)+\eta^4(q)\eta^2(q^2)\eta^4(q^4)$?

12 votes

Why 1728 in $j$-invariant?

12 votes

Graphically locate the axes or foci of an ellipse from 5 arbitrary points on its perimeter.

10 votes
Accepted

Show that $f = x^5 + 5x^3 + 1 \in \mathbb Q[x]$ is irreducible

10 votes
Accepted

Good description of orbits of upper half plane under $SL_2 (Z)$

10 votes

Polynomial roots problems.

9 votes

Foci of a general conic equation

9 votes

About the roots of cubic polynomial

8 votes
Accepted

Finding a quartic polynomial in $\mathbb{Q}[X]$ with four real roots such that Galois group is ${S_4}$.

8 votes
Accepted

Polynomial factorisation - absolute value of coefficients

8 votes

Is there a precise mathematical connection between hypergeometric functions and modular forms

8 votes
Accepted

$q$-series identity

8 votes
Accepted

parallel curvature imply constant Ricci and scalar curvature

7 votes
Accepted

Finding the Norm of an element in a field extension

7 votes
Accepted

Where does Klein's j-invariant take the values 0 and 1, and with what multiplicities?

7 votes

Best algebraic approximations

6 votes
Accepted

On the cubic generalization $(a^3+b^3+c^3+d^3)(e^3+f^3+g^3+h^3 ) = v_1^3+v_2^3+v_3^3+v_4^3$ for the Euler four-square

6 votes
Accepted

Chazy equation and movable singularity

6 votes

How to compute 2-adic square roots?

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