Labelling a Double Axis Graph

We generate a double axis graph, as per the example http://www.mathworks.co.uk/help/matlab/creating_plots/using-multiple-x-and-y-axes.html

However, an error occurs on adding axis labels;

x1 = [0:.1:40];
y1 = 4.*cos(x1)./(x1+2);
x2 = [0:.1:40];
y2 = 4.*sin(x1)./(x1+2);
x3 = [1:.2:20];
y3 = x3.^2./x3.^3;
figure;
hl1 = line(x1,y1,'Color','r');
ax1 = gca;
set(ax1,'XColor','r','YColor','r');
hold all;
hl2 = line(x2,y2,'Color','g');
ax2 = axes('Position',get(ax1,'Position'),...
           'XAxisLocation','top',...
           'YAxisLocation','right',...
           'Color','none',...
           'XColor','k','YColor','k');
hl3 = line(x3,y3,'Color','k','Parent',ax2);
%the above works fine. 
title('My title')

%Now when we try and add labels, we get an error, "Value must be a handle"
set(ax1, 'Xlabel', 'G');
set(ax1, 'Ylabel', 'V');
set(ax2, 'Xlabel', 'D');
set(ax2, 'Ylabel', 'L');

any sensible comments gratefully recieved! thanks!

Answer 1

[Azzi Abdelmalek]

Try

   xlabel(ax1, 'G');