TVM Solver: Correct Loan/Annuity Calculations at i=0

This example demonstrates an interactive time value of money (TVM) solver that computes and updates related financial parameters for annuities/loans, including the important edge case when the interest rate i = 0. It centers on the core TVM concepts of present value (PV), future value (FV), periodic payment (PMT), interest per period, and the number of periods, showing how these quantities can be solved and synchronized within the model. Construction-wise, the GeoGebra setup uses Textfield to manage user inputs and result readouts, and Intersect to connect or determine displayed items based on the model’s underlying constraints. The construction summary references interactive objects such as n, i, pv, pmt, fv, py/cy, multiple inputBox components (inputBox1–inputBox7), and buttons (button1–button7) to trigger the solver and refresh outputs, while result text objects (text1, textn) present computed values. Suitable for high school/early college audiences, especially for teaching financial mathematics and validating solver behavior under special conditions like zero interest.