hjhjhj57's user avatar
hjhjhj57's user avatar
hjhjhj57's user avatar
hjhjhj57
  • Member for 9 years, 9 months
  • Last seen more than 5 years ago
47 votes

How to prove $\operatorname{Tr}(AB) = \operatorname{Tr}(BA)$?

15 votes
Accepted

Prove for any set $E\subset R$ with lebesgue measure 1 there exists a subset with lebesgue measure 1/2.

10 votes
Accepted

Evaluating $\lim_{h \to 0}\frac{(x+h)^{\frac15}-x^{\frac15}}{h}$

9 votes

Easy math proofs or visual examples to make high school students enthusiastic about math

7 votes
Accepted

Orthogonal transformation and vector product

6 votes

Why does the symbol for the multiplication operation change shape?

5 votes
Accepted

Does Convexity play a role in topological equivalence?

5 votes
Accepted

Surface area of a sphere limits

5 votes

How to compute the roots of $x^3 - x^2 - 4x + 4$ = $0$

5 votes

How to evaluate residue of $\cot z/z^4$ at $z=0$?

4 votes
Accepted

How to measure the radius of a sphere?

4 votes
Accepted

Why can characteristic polynomial be calculated using $\det(A - \lambda I )$ or $\det(\lambda I - A)$

4 votes
Accepted

Showing that $\int_{E\cup F}f=\int_E f+\int _F f$, where $E\cap F=\emptyset$

4 votes
Accepted

If an $n\times n$ matrix $A$ is diagonalizable and has only one eigenvalue $\lambda$ with multiplicity $n$, then $A = \lambda I$. True or False?

4 votes
Accepted

How to solve this 3rd degree polynomial?

4 votes
Accepted

Proof my by mathematical induction $\sum_{i=1}^{n} \frac{(-1)^{i-1}}{i} > 0 $

4 votes
Accepted

find the equation of the circle $x^2 +y^2 +ax +by = c$ passing through points $(6,8), (8,4), (3,9)$

3 votes
Accepted

the characteristic polynomial of a linear transformation

3 votes

Proof of formula for the antiderivative of $\sec x$

3 votes

An operation similiar to division of vector?

3 votes
Accepted

Proving dense set is core for a self adjoint operator

3 votes
Accepted

Find an orthogonal basis for W.

3 votes
Accepted

Why does an isomorphism need to be a homomorphism?

3 votes

Can a constant be considered as 1x1 matrix?

3 votes

How does $\log_2(A)-\log_2(B)+\log_2(c)$ not equal $\log_2(\frac{Bc}{A})$

3 votes
Accepted

Find polynomials $q(x)$ and $r(x)$ such that $f(x)=g(x)q(x)+r(x)$ where $r(x)=0$ or $\deg r(x)<\deg g(x)$

3 votes

Is there a mathematical term for three orders of magnitude?

3 votes

Show that $A$ and $A^T$ do not have the same eigenvectors in general

3 votes
Accepted

Linear Map is Homeomorphic in $\mathbb R^k$

3 votes
Accepted

Differential Geometry-Hodge Star

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