How to plot second y axis y2 that is just related to y1 as f(y1)

I have a plot on y1 axis. I would like to have units conversion on axis y2, as f(y1).

How can you plot two units on one graph ? That will assume that horizontally the unit conversion is correct.

Thank you.

x = linspace(0.1,20,100);
y1 = x.^2;
y2 = x^.4./2x; % for example unit conversion for y2 axis no graph to plot
plot(x,x.^2)

Answer 1

[dpb]

plotyy is about the simplest; it computes "nice" axes limits automagically that line up over the ranges of the two axes--

y2 = x.^.4./(2*x);
plotyy(x,y1,x,y2)
legend('y1','y2','location','best')

yields the following: