# Properties of Asymptotic functions

1. Jul 10, 2005

### keebs

I have a few questions about asymptotic functions, and was wondering if anyone could help...

If h(x)~g(x), is h(x+1)~g(x)?
And, if h(x)~g(x), is h(x)h(x+1)~g(x)g(x+1)?

Thanks in advance for any help...

2. Jul 11, 2005

### rachmaninoff

Think about $e^{(x+1)}=e \cdot e^x$; look at the definitions.

3. Jul 11, 2005

### keebs

Ahhh, ok. Thank you.

Last edited: Jul 11, 2005
4. Jul 11, 2005

### Hurkyl

Staff Emeritus
I'm not sure that implication holds in general... I can imagine failure can occur if the functions grow sufficiently fast, or if they can do other odd things, like zig-zag back and forth.

5. Jul 11, 2005

### keebs

What about with the prime counting function? Is pi(x+1)~x/lnx?

6. Jul 11, 2005

### Hurkyl

Staff Emeritus
I think it might be easier to first decide if pi(x) ~ pi(x + 1), or if (x - 1) / ln (x - 1) ~ x / ln x

7. Jul 11, 2005

### keebs

Ah, ok. Because if either one of those is true then it implies that pi(x+1)~x/lnx.