trh@ukc.UUCP (06/19/85)
On computing some large expressions via Macsyma the following statements dn : diff(n,t); dn0 : ev(dn, t=0); produce a `can't differentiate w.r.t a number 0 ' message. Looking at n it contains some expt( long boring expression, <-1>) messages in it, dn then contains d - expt( long boring expression, -1) dt and hence the catastrophe. I've tried all ( well it seems like it!) combinations of simp, expand, diff and eval in ev but I can't get rid of the expt. Please can somebody help. Tim Hopkins, Computing Laboratory, University of Kent, Canterbury CT2 7NF Kent U.K. { trh@ukc.UUCP trh%ukc@ucl-cs.ARPA na.hopkins@su-score.ARPA }