Integration For a Range of Limits

Hi there.

I am trying to use Mathcad to find the probability of a sinking object hitting the seabed within several rings in 10m intervals.

It is quite a simple integration problem using a range of limits.

Basically I have a range for the upper and lower limits, r0 and ri, but they are highlighted as either 'not real', or 'need to be a scalar/vector' (Please see attached sheet)

I have tried putting the variable limits as either Matrices/Vectors as well as a range, but I cannot get it to work. On the attached sheet at the bottom are the individual workings, but I was hoping to generate a list of answers from one general formula.

I am a student and I am very new to Mathcad, I have searched the help section on Matchcad and on this website but I cannot find or think of an alternate way of solving the problem. I appreciate this may be simple and I may not be using Mathcad correctly, but any help, or direction would be much appreciated.

Thanks,

James