# Easy integral question

1. Jan 17, 2005

### Hygelac

THis one just seems wierd, I know it should be easy but for some reason I am having trouble with it :(

What is the anti-derivative of 7x^-1 ?

2. Jan 17, 2005

### Muzza

7ln(x) + C.

3. Jan 17, 2005

### ReyChiquito

$$\int x^ndx=\frac{x^{n+1}}{n+1}+C$$

4. Jan 17, 2005

### Muzza

Using that won't work in this case.

5. Jan 17, 2005

### ReyChiquito

i read the q. wrong :P

but sure it works using the fundamental theorem of calculus

6. Jan 17, 2005

### Muzza

It still doesn't work. If you set n = -1, you'll be dividing by zero...

7. Jan 17, 2005

### Sirus

$$\int \frac{1}{u}\,du=\ln|{u}|+C$$

8. Jan 18, 2005

### ReyChiquito

good point

SEE KIDS what can happen if you dont read the whole question???

*blush* :tongue: