% frcdheat.m % T' = -0.33*( T - (273 - 0.1*t) ) function Tprime = frcdheat(t, T) Tprime = -0.33*( T - (273 - 0.1*t) );Then start

[t,y] = weuler( 'frcdheat', 0, 24, 280, 0.5);to produce a plot of the approximate solution curve. (The 0.5 in the call to

Add labels and a graph of the forcing function to the plot as
follows. To put the ``forcing function'' (actually
the outside temperature in this case) into the vector `z`, type

s = 0:0.5:24; z = 273 - 0.1*s;

The next commands build the plot:

plot(t,y,'o'); % plots y with o's hold on; % holds the old plot plot(s,z,'x'); % plots z with x's title(' Heat-Loss Model '); % adds a title xlabel(' Time (hours) '); ylabel(' Temperature (K) '); % label the axes text(10, 278, ' o temperature inside '); % put text at (10, 278) text(10, 275 , ' x temperature outside '); % put text at (10, 275)

To start over, type `hold off` or close the figure window.

To leave *Matlab* and save your variables into the file `
filename.mat`, type `save filename`. When you return to *
Matlab*, type `load filename` to pick up where you left off.

© 1996 by Will Brother. All rights Reserved. File last modified on November 21, 1996.