Show | ||x|| - ||y|| | < ||x - y||
51120
Is this a valid proof for the reverse triangle inequality: Given $x,\,y\in\mathbb{R}^n$, $\|x-y\|\ge |\|x\| - \|y\||$.
116223
Show that the angles satisfy $x+y=z$
80095
Show $|a|+|b|+|c|+|a+b+c| \geq  |a+b|+|b+c|+|c+a|$ for complex $a$, $b$, $c$
43000
Show $\operatorname{rank}(A) + \operatorname{rank}(B) \ge \operatorname{rank}(A+B)$
46760
To show that $P(|X-Y| \leq 2) \leq 3P(|X-Y| \leq 1)$
68204
How can I label an equation as (*)
108704
Help with proof of $|x+y| \geq |x|-|y|$
67483
Show that $|a-b|<\epsilon \Rightarrow |a|<|b|+\epsilon$
116240
Show a matrix in detail
37252
How can I show that $\begin{pmatrix} 1 & 1 \\ 0 & 1\end{pmatrix}^n = \begin{pmatrix} 1 & n \\ 0 & 1\end{pmatrix}$?
81618
Prove $||a|-|b| | \leq |a-b|$
49240
$\forall x,y \in \mathbb{R}:\vert\cos x- \cos y\vert\leq\vert x-y\vert$
86263
How do we show there are the same number of elements in each of the sets?
52135
Show that $A \setminus ( B \setminus C ) \equiv ( A \setminus B) \cup ( A \cap C )$
110075
How to show the given equality
92543
Regular expressions: Show that A*B is the solution of X = AX + B
152311
Proving expression$\geq 2$, where variables are $x,y,z$