You can give the code below a try or post your own code so we can help you with your train of thought.
x = 1:4000;
y = zeros(length(x));
for ii = 1:length(x)
if x(ii)<=2000
y(ii) = 0.005*x(ii);
elseif (2000<x(ii) && x(ii)<2500)
y(ii) = 10-0.02*x(ii);
elseif x(ii)>2500
y(ii) = 0;
else
fprintf("Error at %0.f\n",x(ii));
end
end
plot(x,y)
