# Tag Info

## Hot answers tagged absolute-value

### Why is absolute value difficult?

(My answer is just a guess and not based on any formal research.) I suspect the absolute value function may be difficult to understand because it involves "negative numbers that aren't negative." ...
• 10.9k

### Why is absolute value difficult?

My experience is that weak students latch onto absolute value of a number is always positive. They are fine working with constants. When you introduce a variable, it all falls apart. To these ...
• 8,017

### Why is absolute value difficult?

In my experience, this is the first really clear example that students experience of dissonance between how something looks and what it is. One of the most common errors I see regarding absolute value ...
• 1,994

• 1,122
1 vote

### How can one lone picture prove the Triangle Inequality, $|x−y|≤|x|+|y|$, $|x|−|y|≤|x−y|$, and the Reverse Triangle Inequality?

You are telling sixteen-year olds that: $$|x - y| \le |x| + |y|$$ ... and you call that "triangle inequality"? ... and your teenage students don't get that? Well, I'm a mathematician and I ...
• 2,175
1 vote

### Is there a pre-calculus introduction to the formal definition of a limit?

Precalc courses differ a lot, so it's hard to say something is included or not. After all there was a time when there didn't even exist a precalc course (different from a strong algebra 2, trig, and ...
• 134
1 vote

### Is there a pre-calculus introduction to the formal definition of a limit?

Perhaps what would best prepare a student for the formal $\epsilon{-}\delta$ definition of a limit is an animation which shows both $\epsilon$ and $\delta$ approaching $0$, $\epsilon \neq \delta$, ...
• 29.9k
1 vote

### Why is absolute value difficult?

IMHO the main issue is that the absolute value doesn't satisfy any simple algebraic rules, so you cannot simplify the expressions including it. The computation itself is no more difficult than the ...
• 3,939

Only top scored, non community-wiki answers of a minimum length are eligible