MATLAB: Want to combine two plots

homeworkplot

I want to plot y1 = 100.0 – 90.0*exp(-0.0465*t); and y2 = 203.6 – 11.3*t; together on the same plot
and then plot ( y = y1 +y2 ) for t = (0,50) but I don't want to include the (-ve) values of y2, i.e replace the (-ve) values of y2 with zero.
something like a new function y3 = [ ( if (t<203.6/11.3) y3 = y2 else y3 = 0 ]

Best Answer

Try this: 
t = linspace(0, 50);
y1 = 100.0 - 90.0*exp(-0.0465*t);
y2 = 203.6 - 11.3*t;
y2 = y2 .* (y2 >= 0);                                   % Set Negative ‘y2’ To Zero 
y = y1 + y2;
figure
plot(t, y)
grid
xlabel('t')
ylabel('y')
That should do what you want.
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