# Int (1/dx)

1. Aug 5, 2010

### Sara991

How do I solve this integral?

$$\int \frac{1}{dx}$$

2. Aug 5, 2010

### vela

Staff Emeritus
You can't. Did you by chance mean

$$\int \frac{1}{x}\,dx$$

3. Aug 5, 2010

### Sara991

Hi dear

I mean:
$$\int \frac{1}{dx}$$

4. Aug 5, 2010

### vela

Staff Emeritus
That expression doesn't make sense. Where did it come from?

5. Aug 5, 2010

### Sara991

I encounter with this, when I am solving a problem.

6. Aug 5, 2010

### HallsofIvy

Staff Emeritus
Then please give the entire problem. As vela said,
$$\int \frac{1}{dx}$$
simply doesn't mean anything.

7. Aug 5, 2010

### Sara991

So Sorry, I am not able to explain it.

8. Aug 5, 2010

### Char. Limit

Well, since $\int dx[/tex] means a sum ([itex]\int$) of an uncountably large amount of infinitesimally small numbers (dx's)...

and since, if dx is infinitesimally small, 1/dx would be uncountably large...

Then $\int \frac{1}{dx}$ means a sum of an uncountably large amount of uncountably large numbers...

and so is uncountably large itself.

9. Aug 5, 2010

### Hurkyl

Staff Emeritus
Ugh, first the opening poster won't go into where she got the expression so we can point out what she did wrong, but now people are giving her questionable advice.