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Jun
18
answered What is the intuition behind contours and their geometric properties
Jun
18
comment Norm of Hilbert matrix is it equal to $\pi$?
The one about the norm being an algebraic number? The norm is obtained by solving an optimization problem. Just verify that the Karush-Kuhn-Tucker conditions for this problem are equations and inequalities involving algebraic functions, so the solution comes from solving a system of algebraic equations.
Jun
18
comment Linear PDE with Variable Coefficients Help
That in itself is not sufficient. Some appropriate condition at $+\infty$ might work.
Jun
18
comment Linear PDE with Variable Coefficients Help
$u(x,0)=1$ is going to be impossible, because the exponential function is not a linear combination of $Ai$ and $Bi$. You need to, in some sense, combine these for infinitely many different $\lambda$'s: that's essentially what the Laplace transform approach does.
Jun
17
answered Linear PDE with Variable Coefficients Help
Jun
17
comment Linear PDE with Variable Coefficients Help
Since your pde is second-order in $x$, surely you need an additional boundary condition. And do you have any reason to believe there is a closed-form solution?
Jun
17
comment Norm of Hilbert matrix is it equal to $\pi$?
Note that the OP mentioned ${\mathbb R}^n$, but said nothing about $n \to \infty$. Still, you may be right.
Jun
17
answered Norm of Hilbert matrix is it equal to $\pi$?
Jun
17
revised The behavior of a solution to a parametrized equation
added 298 characters in body
Jun
17
revised The behavior of a solution to a parametrized equation
added 167 characters in body
Jun
17
answered The behavior of a solution to a parametrized equation
Jun
17
answered Solution of the equation $(x^2-x-1)^{x+2}=1$ in $\mathbb{Z}$
Jun
17
answered Independence of random sum variables
Jun
17
comment What are origins of the Laplace variable $s$
When you ask "what are its origins", are you asking for historical answer or a conceptual one (i.e. "can the Laplace transform be thought of as a particular case of some more general structure")?
Jun
17
answered Sinus curve with elbows / round steps?
Jun
17
answered Integrating $1/\sqrt{z^{2}-1}$ on some contour
Jun
17
comment Measurability of a function in $\mathcal{B}(\mathcal{C}([0,1],\mathbb{R}))$
$\lambda$ is Lebesgue measure?
Jun
17
answered Solution of the ODE $\sum_{k=0}^N\frac{d^k}{dt^k}x(t)=0$
Jun
17
answered $\gcd\left(\binom{n}{k},n\right)>1$ for nontrivial values?
Jun
16
awarded  Nice Answer