[newbie] 'inverse laplace' question



Am Freitag, den 22.01.2010, 10:17 +0100 schrieb Hugo Coolens:
> Is there a reason why Maxima doesn't solve the following example:
> 
> ilt(exp(-a*s)/s,s,t);
> 
> I expected a heaviside step shifted over a, but maxima just leaves it as 
> it is.

Sorry, but the inverse laplace transform of your example is not
implemented. This is a missing feature. 

Please have a look at the documentation. It is documented that ilt only
works for a ratio of polynomials.

(%i12) ? ilt

 -- Function: ilt (<expr>, <s>, <t>)
     Computes the inverse Laplace transform of <expr> with respect to
     <s> and parameter <t>.  <expr> must be a ratio of polynomials
     whose denominator has only linear and quadratic factors.  By using
     the functions `laplace' and `ilt' together with the `solve' or
     `linsolve' functions the user can solve a single differential or
     convolution integral equation or a set of them.

Dieter Kaiser