# Calculator not working for me

1. Dec 7, 2013

### oneamp

I am using the PDF for log-normal distribution, which I'm referencing off the wikipedia page:
here. I am integrating from 0 to infinity with my TI-89. It is not giving me 1, as I'd expect from a PDF, but is giving me infinity. Here is how I'm entering it in the calculator (I've tried a few variations):

e^(-((ln(x-1))^2/2))/(sqrt(2*pi)*x)

mu and sigma are one, so it simplifies to this. What is going on :(

Also I just tried integrating from 0 to 12, and it also says infinity. I guess I am doing something wrong :(

Thank you

Last edited: Dec 7, 2013
2. Dec 7, 2013

### mathman

Your exponent is wrong. It should be ((lnx - 1)2)/2.

3. Dec 7, 2013

### oneamp

thank you

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