To do this, we set up CUMPRINC like this:
rate- The interest rate per period.
pv- The present value, or total value of all payments now, 5000, from cell C5.
end_period- the last period of interest, 60 in this case for the full loan term.
With these inputs, the CUMPRINC function returns 5,000, which matches the original loan value as expected.
