% % Filename: payments.m % % Description: This matlab m-file computes monthly loan payments % given the amount borrowed, the number of months % financed, and the annual interest rate. It then % plots the principle and payments as a discrete-time % signal. % P = input('Enter amount borrowed: '); N = input('Enter number of months financed: '); iy = input('Enter the annual interest rate in percent: '); im = iy/(12*100); % compute monthly interest rate % not in percent A = P*((im*(1+im)^N)/((1+im)^N-1)); % compute payment amounts n = 0:N; % define time periods (months here) CF = [P -A*ones(1,N)]; % compute discrete-time signal % representing cash flow stem(n,CF); % plot cash flow as a discrete-time % signal xlabel('n'); % label plots ylabel('cash flow'); title('Plot of Loan Cash Flow');Run payments.m by typing payments at the matlab prompt after saving it in a working directory:
>> payments Enter amount borrowed: 1000 Enter number of months financed: 12 Enter the annual interest rate in percent: 16.9MATLAB Plot Generated:
The plot was printed by typing 'print' at the matlab prompt when the plot was displayed in the graphics window.