plotting dashed lines



I've tried to understand the Maxima and gnuplot documentation as to how
to get a plot with one curve as a dashed line but to no avail. For
example, suppose I plot a function and its asymptote,

plot2d([1/(x-1),[parametric,1,t,[t,-10,10]]],[x,-2,4],[y,-10,10])

but want to make the asymptote dashed. How do I accomplish this?

The Maxima manual sends me to gnuplot documentation but I can't figure
out that documentation enough to get a dashed line.

Thanks for any pointers, Bob
-- 
Dr. Robert J. Jerrard, Professor of Mathematics,
Concordia University College of Alberta,
7128 Ada Blvd., Edmonton, Alberta, T5B 4E4, Canada.
Phone: (780) 479-9291, Fax: (780) 474-1933.