Another solution to the problem of finding the interior points and limit points of $A=\{(x,y):x^2+2y^2<1\}$
64523
interior points and limit points of $\{(x,y): x^2+2y^2 < 1\}$
132070
A challenge on the parabola
51019
Polynomial problem with two conditions
71358
A very interesting question: intersection point of $x^y=y^x$
59419
Crafty solutions to the following limit
30423
interior points and convexity
111443
Optimization of $2x+3y+z$ under the constraint $x^2+ y^2+ z^2= 1$
62161
Solutions of the Pell-type equation $x^2-2y^2=-1$
158447
Limit as $(x,y)$ approaches $(0,0)$ of $(1+x^2+y^2)^{\frac{1}{x^2+y^2+xy^2}}$
77464
Prove that ${x dy - y d x\over x^2 + y^2}$ is not exact
63074
The equation of a family of circles passing through two given points
90261
Find all solutions of the equation $n^m=x^2+py^2$ which satisfy the following properties
33310
Proving that the set of limit points of a set is closed
155004
Maximal points on an $n$-dimensional ellipsoid
18152
Find the limit points of the set $\{ \frac{1}{n} +\frac{1}{m} \mid n , m = 1,2,3,\dots \}$
36063
Finding the limit of $(1-\cos x)/x^2$
137745
Substitution in determining limit of polynomials