[Maxima] Laplace transform / unit step / present value

[Daniel Lakeland]

Today I noticed that the present value of a cash flow is the same as
the laplace transform of that cash flow evaluated at s = r, the
interest rate. This gives me a very nice way to deal with my windowed
cash flow problems, especially since the laplace transform of a
delayed step function is known.

However, I can't figure out how to tell maxima to take the laplace
transform of a step function. Does it know about such things? 

perhaps we need to define a heaviside step as a fundamental function
in maxima, and tell the laplace operator about it?? Or is it already
defined and I simply don't see it in the docs?



-- 
Daniel Lakeland
dlakelan at street-artists.org
http://www.street-artists.org/~dlakelan