1.-获取MATLAB workspace中的数据

fileID=fopen('data_in.txt','r');

A=textscan(fileID,'%f %f %f')

h=A{:,1};    % altitude
y1=A{:,2};   % 2nd column
y2=A{:,3};   % 3rd column

2.-第2列和第3列

figure;
plot(h,y1)
grid on
title('row data')
xlabel('h');

hold on
plot(h,y2)
legend({'y1','y2'},'Location','northeastoutside')

3.-或者按阶段，应该理解以下内容

figure;
plot(h([1:end-1]),diff(y1))
grid on
title('dy1/dt   dy2/dt')
xlabel('h');

hold on
plot(h([1:end-1]),diff(y2))
legend({'y1^{\prime}','y2^{\prime}'},'Location','northeastoutside')

也许y1y2已经是度了。请让我们知道，谢谢。