# Quick question on notation

1. Apr 29, 2005

### zeta101

Hi,

How would you write mathematically "As P approaches zero from the negative side". Is it something like P --> -0 ?

Thanks!

2. Apr 29, 2005

### Data

the usual notation is
$$\lim_{x \rightarrow 0^-}.$$

3. Apr 29, 2005

### shmoe

You'd want the 'minus' where an exponent would be, usually something like $$P\rightarrow 0^{-}$$

4. Apr 29, 2005

### AKG

$P \to 0^-$. The "-" is on the right side of the number, which makes sense because this way you can use it for negative or positive numbers, otherwise, how could you tell if you meant that P was approaching -5, or approaching positive 5 from the left? So "-" means approaching from the left, and in the case of positive numbers, the left isn't "the negative side" (although it is closer to the negative numbers). Also, this could be written as: $P \uparrow 0$ but you don't see that most of the time.

5. Apr 29, 2005

### zeta101

Thank you all for the answers!