Question

MATLAB中plot([0 x1],zeros(1 ,length(A)+1),'r');是什么意思？

Answer 1

plot是画图，画zeros(1,length(A)+1)关于[0 x1]的图像，[0 x1]相当于x,zeros(1,length(A)+1)相当于y，画y(x)。'r'表示线的颜色为红色(red)

追问

A = zeros(1 ,length(x2));
B = zeros(1 ,length(x2));
......
subplot(1,2,2)
plot(A,B,'*');
hold on
axis tight
plot([0 x1],zeros(1 ,length(A)+1),'r');

zeros(1,length(A)+1)相当于y，也就是B，length(A)+1为什么要加1？