shall I use 'plotyy' to plot two curves from the same starting point?

I use plotyy to plot as below picture:

Just you see, the red curve starts from point A; and the blue curve starts from point B;

my question is that shall I set something to red and blue curves start from the same point? Or I should say make point A and point B to become the same point?

Answer 1

[Walter Roberson]

You can manipulate xlim and ylim for the axes so that the points coincide, but I am not convinced that it is meaningful to do so considering the very different scales.