xmaxima : how to declare a positive scalar?



Hi Blair,

2006/2/18, Blair Smith <bmsmith at lsu.edu>:
>
>
> The more basic question is how can one declare a symbol a positive scalar
> to perhaps help Maxima determine a valid solution? (e.g., I can make sure
> the cone axis does not lie in a zy plane to ensure the ellipse is
> well-defined)


You can use assume command, for example:

(%i9) integrate(1/x,x,a,4);

Is  a - 4  positive, negative, or zero?

pos;
(%o9)                           LOG(4) - LOG(a)
(%i10) assume(a > 4);

(%o10)                              [a > 4]
(%i11) integrate(1/x,x,a,4);

(%o11)                          LOG(4) - LOG(a)


Good bye,


--
Juan Pablo Romero Bernal
Grupo Linux Universidad Distrital

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