Hi,
I am a beginner in Maxima; I try to work with simple "constrained" variables and understand how maxima can make "indirect" deductions of expressions where they appear.
Here is a simple script to explain:
forget(facts());M : matrix([a, b],[c,d]);assume(equal(determinant(M),0), a>0, b<0, notequal(d,0));
sign(a/b)=> the answer is "neg" which is OK
sign(c/d)=> the answer is "pnz" which is not wrong but not best, as c/d=a/b<0
Is there a syntax so that Maxima deduce "indirectly" the answer sign(c/d)<0?Otherwise, these assumptions would lack some interest...
Thanks.
Best regards,Philippe