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Dario's user avatar
Dario's user avatar
Dario
  • Member for 9 years, 10 months
  • Last seen this week
47 votes

How to distinguish between walking on a sphere and walking on a torus?

14 votes
Accepted

How can I solve this O.D.E.?

14 votes

How do i find $(1+i)^{100}?$

12 votes
Accepted

Prove the equation

11 votes

Can product of two singular matrices be invertible?

9 votes
Accepted

Show that $\sqrt{8-4\sqrt3} =\sqrt[6]2\:\! {\sqrt[3]{12\sqrt3-20}}$

8 votes

Homotopy equivalent iff isomorphic homotopy groups?

8 votes

Is the distance function differentiable?

7 votes
Accepted

Hint for solving $ y (y')^2 + (x-y) y' - x = 0$

7 votes
Accepted

Shorter solution to differential equation?

7 votes

Show that $B$ is invertible if $B=A^2-2A+2I$ and $A^3=2I$

7 votes

The inequality $x^{6}-x^{5}+x^{4}-x^{3}+x^{2}-x+3/4 >0$ holds for all $x\in\mathbb R$

7 votes

Embedding a torus in $\mathbb{R}^{n+1}$

6 votes
Accepted

finding an acyclic but not contractible space

6 votes
Accepted

Fundamental Group of a Hexagon with Edge Identifications

6 votes
Accepted

Extending a Homeomorphism between open ball and bounded open subset of $R^n$

6 votes

Hatcher 2.2.26 Show that if $A$ is contractile in $X$ then $H_n(X,A) =H_n(X) \oplus H_{n-1} (A)$

6 votes

How do I simplify $\log (1/\sqrt{1000})$?

6 votes
Accepted

Cannot solve differential equation

6 votes

Distance between two points in spherical coordinates

6 votes

Boundary of an open ball in $\mathbb{R}^{n}$ homeomorphic to $\mathbb{R}^{n-1}$

6 votes
Accepted

Evaluate the limit $\lim_{x\rightarrow 0}\left[ \frac{\ln(\cos x)}{x\sqrt{1+x}-x} \right]$

5 votes
Accepted

complex numbers quadratic equation question

5 votes

Is $\sqrt{x}$ concave?

5 votes

How can I prove that a square matrix is invertible if it satisfies this polynomial equation?

5 votes

Uniform and point wise convergent

5 votes
Accepted

Homotopic equivalence for $S^5$ without three $S^1$

5 votes
Accepted

The annulus with with antipodal points on the outer circle identified gives a mobius strip

5 votes
Accepted

$Res(f,z_0)=0\implies f $ is analytic at $z _0 $?, $z _0 $ is a simple pole.

5 votes

for which a, the matrix A is diagonalizable?

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