# Evaluate the integral

1. Sep 28, 2008

### albireo

1. The problem statement, all variables and given/known data

Integrate 1/sqrt(x^2+16)

The answer I get is :
ln ((sqrt(16+x^2)+x)/4)+C

and it is incorrect. The answer is ln(sqrt(16+x^2)+x) + C

2. Sep 28, 2008

### gabbagabbahey

Hint:

$$ln(a/b)=ln(a)-ln(b)$$

3. Sep 28, 2008

### albireo

but ln4 is not =0

4. Sep 28, 2008

### gabbagabbahey

No, but $$C- ln(4)$$ is still just a constant. Basically, your solution is correct but it is also equivalent to the other solution just with a different value of $$C$$.

5. Sep 28, 2008

### albireo

Of course! Thanks a lot:)