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Nov
29
accepted Finding the zero divisiors of $\mathbb{Z}_{n}$
Sep
30
accepted Prove that $2^n>n^4$ for all $n\geq 17$
Sep
29
accepted Cubic polynomial and its discriminant
Sep
22
accepted Prove that $(\mathbb{R}\setminus \{0\},\sim):= ab>0$ is transitive.
Sep
22
accepted Determine whether the function $\alpha:A\times B\rightarrow B\times A$ where $\alpha((a,b))=(b,a)$ is injective and/or surjective
Sep
22
accepted Give an example of two functions $\alpha,\beta$ on a set $A$ such that $\alpha\circ\beta=\mathsf{id}_{A}$ but $\beta\circ\alpha\neq\mathsf{id}_{A}$.
Sep
22
accepted Proving that $\alpha:\mathbb{R}\to\mathbb{R}$ where $\alpha(x)=\frac{x^{3}}{x^{2}+1}$ is bijective
Sep
19
accepted Show that $A\setminus (B\setminus C)=(A\setminus B)\cup(A\cap B\cap C)$
Mar
4
accepted How do I design a generating function to count subsets of distinct objects?
Feb
2
accepted How to tell if I am double counting in a combinatorics problem?
Dec
17
accepted How does the triangle inequality work for $|x-y|$?
Nov
4
accepted Finding the matrix of a linear transformation relative to two non-standard bases
Oct
23
accepted What is an “incongruent” solution?
Oct
14
accepted What is an intuitive definition of the zero vector?
Oct
14
accepted Construct a basis for $\mathbb{R}^4$ given two vectors and any two of the standard basis vectors in $\mathbb{R}^4$
Oct
14
accepted Number theory GCD word problem
Oct
14
accepted Can a matrix have a null space that is equal to its column space?
Oct
14
accepted If matrices $B$ and $AB$ have the same rank, show that they have the same null spaces.
Oct
14
accepted Prove that the Diophantine equation $ax+by+cz=e$ has a solution if and only if $(a,b,c)\mid e$.
Oct
14
accepted Formally prove: $\lim_{n\to\infty}x_n=L_1\Longrightarrow\lim_{n\to\infty}x_{n+k}=L_1,\forall k\in\mathbb{N}$