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user289143
  • Member for 6 years, 7 months
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9 votes
Accepted

Prove that $∂A$ is closed given $∂A = \text{Cl}(A) − \text{Int}(A)$

8 votes

$100$ birds in $21$ cages each with $≤ 10$, with least cages having $≥ 4$ birds?

7 votes

Does there exist a matrix $A$ such that $\|Ax\|_{\infty} = \|x\|_1$?

6 votes
Accepted

How do I solve $\sqrt{x-\sqrt{x-\sqrt{x...}}}=9 \Rightarrow x=?$

5 votes
Accepted

Show that the solutions is a subspace of $\mathbb R^5$

5 votes
Accepted

Summing cube roots in fractions

5 votes
Accepted

$\omega$ is a solution of $x^2+x+1=0$, find $\omega^{10}+\omega^5+3$

5 votes
Accepted

Find coefficient of $x^ky^m$ in $(x+y-1)^n$

4 votes

probability of picking a winner

4 votes
Accepted

Finding area of rhombus

4 votes
Accepted

Find the formula of the linear transformation

4 votes

If $m,n\in Z$ then {$x\in Z: mn\mid x$}$\subset${$x\in Z:m|x$}$\cap${$x\in Z:n\mid x$}

4 votes
Accepted

Let $A$ be a square matrix, such that $A^3 = I$. If 1 is not an eigenvalue of $A$, show: $A^{2} + A + I = 0$

4 votes
Accepted

$p_1,p_2$ roots of $x^2+3x+5=0$, then the value of the expression $M=\frac{p_1^2+5p_1+7}{p_1^2+7p_1+5}+\frac{p_2^2+5p_2+7}{p_2^2+7p_2+5}$

3 votes
Accepted

Show that $\frac{1+i}{\sqrt{2}}$ is in the splitting field of $x^8 - 3$ over $\mathbb{Q}$

3 votes
Accepted

Factoring $z^4+64=0$

3 votes

$k=-\sqrt{3}(\sqrt{5+2\sqrt{6}}+\sqrt{5-2\sqrt{6}})$

3 votes
Accepted

Polynomial with integer coefficients: given values at point find minimal value for a point

3 votes

Derivative of $x^{\sin x}$

3 votes
Accepted

$\overline{A}=\overline{B}$ implies $\partial A=\partial B ?$

3 votes

Why isn’t $f:\!R \rightarrow P : a \rightarrow ax^3 + a^2x^5$ a linear operator?

3 votes

Homeomorphism: can $f:X\mapsto X'$ be continuous, bijective without $f^{-1}:X'\mapsto X$ being continuous?

3 votes
Accepted

Determine if $R \subseteq A \times A$ is reflexive, transitive, symmetric, antisymmetric

3 votes
Accepted

Why $f(x) = 5x$ is not a ring homomorphism?

3 votes

To solve $ y'+y=|x|$

2 votes
Accepted

Find the value of $\frac{t^{4012}+37}{2}$

2 votes

Constraints on the roots to a quadratic equation

2 votes
Accepted

Question Regarding Open Sets

2 votes
Accepted

What is the cartesian equation of a line in $\mathbb{R^n}$?

2 votes
Accepted

Why $ax + by + c = 0$ if $y = ax + c$?

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