Plus42 Equations, Preview Release

[Albert Chan]

(06-08-2022 12:46 PM)Thomas Okken Wrote:  there is a bug in PMT. In BEGIN mode, it should divide the calculated value by 1+i
(where i is the interest rate per period), and instead it multiplies by that factor.

Fix coming shortly!

There is an intuitive way to get the correct factor. Think of n+1 cash flows.

BEGIN mode ⇒ [pv + pmt, pmt, pmt, ..., pmt, fv]

This is equivalent to all payments paid late 1 period, with a bit of interest penalty.

END mode ⇒ [pv, pmt*(1+i), pmt*(1+i), ... pmt*(1+i), fv + pmt*(1+i)]

Shifted to END mode, we are really solving for pmt*(1+i)
To recover payment, BEGIN mode, we *divide* by (1+i)