Show that $\iint_R \frac{x-y}{(x+y)^3}\,dx\,dy$ does not exist over $R=[0,1]\times[0,1]$
110731
How to compute $\int_{0}^{1}\int_{0}^{1} \frac{x-y}{(x+y)^3} dxdy$
16644
Why does cancellation of dots $\frac{\partial \dot{\mathbf{r}}_i}{\partial \dot{q}_j} = \frac{\partial \mathbf{r}_i}{\partial q_j}$ work?
108955
Showing $(\mathbb{Q},+)$ is not isomorphic to $(\mathbb{R},+)$
141937
Prove that the $\lim_{(x,y) \to (0,0)}h(x,y)$ Does not Exist using Polar Coordinates
153272
Basic question about $\sup_{x\neq 0}{} \frac{\|Ax\|}{\|x\|} = \sup_{\|x\| = 1}{\|Ax\|} $, $x \in\mathbb{R}^n$
154612
$\int_{0}^{x} f(t) dt \ge {f(x)}$ holds or not on $[0,1]$
11259
Prove $R\times S$ is not an integral domain
114198
Showing that $y$ is irreducible in $\mathbb R[x,y]/(x^2+y^2-1)$.
39583
ii) Show that $u$ is not a real part of the function which analytic on $\mathbb{C} \backslash \lbrace 0 \rbrace$
57981
Alternative proof of $a\times0= 0$
98377
How can I prove this limit doesn't exist?
114813
Proof: in $\mathbb{R}$, $((0,1),|\cdot|)$ is not compact.
3296
Proof That $\mathbb{R} \setminus \mathbb{Q}$ Is Not an $F_{\sigma}$ Set
93606
Showing that $C[0,1]$ is not complete
77464
Prove that ${x dy - y d x\over x^2 + y^2}$ is not exact
90055
Show that $\mathcal P(x)\notin x$
106609
Show that $e^{iy} = 1 + iy + \frac{\mu_1 y^2}{2}$ for all $y \in \mathbb{R}$ with $|\mu_1| \leq 1$