matlab 在同一坐标系画出cosx cos2x cos 3x cos 4x,运行后只有两条_百...答:可这样改:clf x=0:0.01:pi;y1=cos(x);y2=cos(2*x);y3=cos(3*x);y4=cos(4*x);a=plot(x,y1,'r');grid on hold on pause plot(x,y2,'g');pause plot(x,y3,'b')pause plot(x,y4,'y')legend('cosx','cos2x','cos3x','cos4x')hold off ...