Start plot at origin

Hi, I made this graph but I don't know how I can make both plots start at the origin (0,0). So the starting point of Y needs to be zero.

plot(tv,gnegate(d(:,3)),'r'); hold on; plot(tv,(r),'b')

Answer 1

[Voss]

data1 = gnegate(d(:,3));
data2 = r;

data1_plot = data1 - data1(1);
data2_plot = data2 - data2(1);

plot(tv,data1_plot,'r'); hold on; plot(tv,data2_plot,'b')