% Matlab script to plot the function y = f(x)
% where f(x) is a polynomial and the range and 
% coefficients of the polynomial are specified by the user.

% Get the values from the user
xrange = input('Enter the range of x values [a b]: ');
coef = input('Enter the coeffients of y=Ax^3 + Bx^2 + Cx + D [A B C D]: ');

% Create the points to plot
xx = xrange(1):0.1:xrange(2);
yy = polyval(coef,xx);

% Plot the points
plot(xx,yy);