HP 50g Graphing Calculator - Manual (Page 456)

Page 13-21
Using the calculator, we proceed as follows:
Alternatively, you can evaluate the integral to infinity from the start, e.g.,
Integration with units
An integral can be calculated with units incorporated into the limits of
integration, as in the example shown below that uses ALG mode, with the CAS
set to Approx mode. The left-hand side figure shows the integral typed in the
line editor before pressing `. The right-hand figure shows the result after
pressing `.
If you enter the integral with the CAS set to Exact mode, you will be asked to
change to Approx mode, however, the limits of the integral will be shown in a
different format as shown here:
These limits represent 1 ×1_mm and 0×1_mm, which is the same as 1_mm and
0_mm, as before. Just be aware of the different formats in the output.