Plotting two axes in gnuplot

Question

Is it possible to plot two curves, with two corresponding axes in gnuplot, each of which has a different scale?

For example, y=x**2 and y=x**4 in the same graph (they vary enough to be "uncomfortable" when plotted with the same scale).

Answer 1

You can have the axes handled automatically without you having to scale them yourself and keep auto-scaling:

set terminal jpeg
set output 'graph.jpg'

set xrange [-10:10]
set ytics 10 nomirror tc lt 1
set ylabel '2*x' tc lt 1
set y2tics 20 nomirror tc lt 2
set y2label '4*x' tc lt 2
plot 2*x linetype 1, 4*x linetype 2 axes x1y2

Answer 2

It is possible to set different ranges for y and y2 (the right axes), and even to set the color of the labels/tics independently.

Then we simply divide the second function by 2 (or something appropriate) and set the colors... as in this example:

set xrange [-10:10]
set yrange [-20:20]
set y2range [-40:40]

set ytics 10 nomirror tc lt 1
set ylabel '2*x' tc lt 1

set y2tics 20 nomirror tc lt 2
set y2label '4*x' tc lt 2

plot 2*x linetype 1, 4*x/2+.5 linetype 2