W. mu

 6 If $v^TAv = v^TBv$ for all constant vectors $v$ and $A,B$ are matrices, is it true that $A=B$? 4 A curious observation regarding eigenvectors of $3 \times 3$ matrices - Hoffman and Kunze's *Linear Algebra* 4 Since $\int \frac{df(x)}{dx} dx = f(x)+c$, can we cancel $dx$ and write $\int df(x) = f(x)+c$? 3 Given $X$ enumerable, prove that always exist a metric in which every $p\in X$ is a limit point 3 How to evaluate the finite sum.

### Reputation (760)

This user has no recent positive reputation changes

### Questions (12)

 5 a limit about exponential function [duplicate] 3 What is the value of the series $\sum_{n\geq 1}\frac{1}{n^2+1}$? 2 How to solve linear differential-difference equation? 2 About the matrix representation of group algebra 1 How to prove that most of the systems of PDEs cannot be decoupled?

### Tags (58)

 11 matrices × 4 5 proof-verification × 4 10 linear-algebra × 6 5 integration × 2 6 calculus × 6 4 eigenvalues-eigenvectors 6 real-analysis × 6 3 sequences-and-series × 4 6 vector-spaces × 3 3 multivariable-calculus × 2

### Accounts (6)

 Mathematics 760 rep 310 MathOverflow 131 rep 3 Physics 106 rep 1 Mathematica 101 rep TeX - LaTeX 101 rep