clc;clear;close all;
x=-2*pi:0.5:2*pi;
y=atan(x);
plot(x,y);
grid;
annotation('arrow',[0.1 0.9],[0.517,0.517],'Color','b') annotation('arrow',[0.517 0.517],[0.1,0.9],'Color','b')运行结果如下