h = 50; %我觉得这里应该是50;
dt = 0.01;
t1 = [0:dt:2/3*pi];
t2 = [2/3*pi:dt:2*pi];
s1 = 25-25*cos(1.5*t1);
s2 = h*ones(size(t2));
plot([t1 t2],[s1 s2])