# Math Help - Integral help

1. ## Integral help

evaluate the integral 1/2x at interval (1,9).

I know the derivative of the integral is ln(x) + C...but I can't figure out how to solve it after spending so much time....

I assumed you would do this..

2*ln(9) - 2*ln(1)...but it's wrong as I got 2*ln(8) and the answer is ln(3). Please help!

2. it is $(1/2)ln(9)- (1/2)ln(1)$
The first step you do is move the 1/2 outside the integral so it just gives you 1/x inside the integral

3. Ok, then you make it ln(9)^ (1/2) right to get ln(3)..that's how I got to the answer, but it makes more sense now..thanks