"MES" using Notes, Solver and CAS variables

[CR Haeger]

Here is my first swing at trying to create a multiple equation solver within the HP Prime. It certainly does not have features of the HP50G MES, but for me its useful enough for daily work. Basically, it is saved notes of CAS commands that can be copied/excecuted as needed. Once setup, I think this may save lots of typing later.

1. I created the following note "FinEqs" in Prime using algebraic format

F_A1:=fv=av*((1+rate)^per-1)/rate;
F_P1:=fv=pv*(rate+1)^per;
P_A1:=pv=av*(((1+rate)^per-1)/(rate*(1+rate)^per));
P_G1:=pv=gv*(((rate+1)^per-1)/(rate^2*(rate+1)^per)-per/(rate*(rate+1)^per));
Solve.E1:='F_A1';
Solve.E2:='F_P1';
Solve.E3:='P_A1';
Solve.E4:='P_G1';

2. Within FinEqs note, select shift/copy, All, Copy to load to clipboard

3. Within CAS (set to approx), shift/paste/1/Enter to paste to command line then Enter. This saves F_A1 etc to CAS variables as equations and loads the equations into E1-E4 in Solve App.

4. Within CAS, you can now solve for terms algebraically using say solve(F_A1,per) (returns {(-ln(av)+ln(fv*rate+av))/ln(rate+1)} for me)

5. Within the Solve App, you can solve equation(s)** numerically after accepting new user variables. Note - you should delete these user variables if not needed afterwards (Vars User Del).

Please comment on or improve this. Thanks to HP Team and experienced users for advice to date.

Best,
Carl

**Check that multiple equations solved simultaneously are correct and meaningful. For example, enabling E1 and E2 in Solve, with fv:2.0, rate:0.1 and per:10 fixed yield av:0.125 (annual or periodic pmt) and pv:0.771. In this case, I solved for two ways (av, pv) to achieve the target fv, given the rate and per(iods). This is not the same as starting with a pv and adding av payment per period.