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0 votes
1 answer
22 views

How to more formally prove this inequality

This is a simple problem I came up with while doing another problem: Given: $n < (n + \frac{1}{2}) < y < (n + 1)$ Prove: $|y - n| > |y - (n + 1)|$ So how I proved it was simply using the ...
Bob Marley's user avatar
0 votes
2 answers
2k views

Absolute Value Proof By Cases

I'm currently working through D. Velleman's How to Prove it. I have a question regarding an absolute value proof by cases (#10; section 3.5). The question asked is to prove that: $$ \forall x\in\...
tom's user avatar
  • 25
1 vote
1 answer
54 views

My proof of: $|x - y| < \varepsilon \Leftrightarrow y - \varepsilon < x < y + \varepsilon$

Is it reasonable to prove the following (trivial) theorem? If yes, is there a better way to do it? Let $x, y \in \mathbb{R}$. Let $\varepsilon \in \mathbb{R}$ with $\varepsilon > 0$. $\textbf{...
Freshman's user avatar
  • 399