Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

Let ∈ < 0.

[Don't worry about it if you don't get it]

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

We should probably be worrying more if we **do** get it.

Why did the vector cross the road?

It wanted to be normal.

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**KelvinKing****Member**- Registered: 2006-04-05
- Posts: 2

not understand......can u explain?

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

In dealing with limits, sets, and sequences, just about every single proof starts off with the line:

Let ∈ > 0.

It reached a point where ∈ is pretty much just assumed to be a positive real number.

*Last edited by Ricky (2006-04-10 04:16:32)*

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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