Can we assure $\frac{d^2}{dx^2} G(\textbf{r},\textbf{r}') = \frac{1}{3} \delta (\textbf{r}-\textbf{r}')$?
71885
Derivatives of $ \frac{1}{r} $ and Dirac delta function
70028
Direct way of calculating $\mathbb{E} \left[ \frac{\textbf{h}^{H} \textbf{y}\textbf{y}^{H} \textbf{h}}{ \| \textbf{y} \|^{4} } \right]$
158852
If $\{v_1, v_2, v_3\}$ is an orthonormal basis of $\mathbb{R}^3$ and $v = a_1v_1 + a_2v_2 + a_3v_3$, can we have $|a_1| > 3$?
33691
Confusion about a particular differential form being exact?
103308
Showing that $\nabla\times(\nabla\times\vec{A}) = \nabla(\nabla\cdot\vec{A})-\Delta\vec{A}$
89186
Showing that $\frac{X_{(i)}}{X_{(n)}},i=1,2,...,n-1$ and $X_{(n)}$ are independent for a population with df $F(y)=y^{\theta}$
23836
Rigorous proof that $\frac{1}{3} = 0.333\ldots$
47385
Is $F = G\dfrac{{m_1}{m_2}}{r^2}$ really true?
67350
Analytic solution of: ${u}''+\frac{1}{x}{u}'=-\delta e^{u}$
128355
Does $e^{tx} + x = t - 1$ yield a solution/s to $\frac{dx}{dt} = \frac{e^{-tx} - x}{e^{-tx} + t}$?
43430
What exactly does $\frac{dx}{dy}$ mean?
11710
How to show that $\mathbb{Q}$ is not $G_\delta$
156636
The Existence of the $^1D$ term and the non-existence of the $^3D$ term?
105707
A proof of $\int_{0}^{1}\left( \frac{\ln t}{1-t}\right)^2\,\mathrm{d}t=\frac{\pi^2}{3}$
152895
What is wrong with this derivation of $\frac{d}{dx}x^2$?
9211
$\int\frac{dx}{x-3y}$ when $y(x-y)^2=x$?
2129
Showing that the derivative operator is not bounded on $L^2 (\mathbb{R})$