Hello list, hello Volker [1],
the command
solve_rat_ineq(ineq=abs(x-1)/abs(x-5) <= 1/3)
yields
[[x == -1, -6 != 0, -6 != 0], [x == -1, -6 != 0, -6 != 0, -6 != 0], [x
== -1, -6 != 0, -6 != 0], [x == -1, -6 != 0, -6 != 0, -6 != 0], [x == 2,
-3 != 0, -3 != 0], [x == 2, -3 != 0, -3 != 0, -3 != 0], [x == 2, -3 !=
0, -3 != 0], [x == 2, -3 != 0, -3 != 0, -3 != 0], [x == 1], [1 < x, x
< 2], [-1 < x, x < 1]]
, which is a disjunctive normal form with unevaluated inequalities
(which are probably explained by [2] and therefore fixable by 'is()').
What's the best way to reduce this to the equivalent
[[-1 <= x, x <= 2]] ?
Should I implement a corresponding method by myself or is there some
functionality already available?
Currently my students still have to use Mathematica, which works as
expected:
In[1]:= Reduce[(2*Abs[-1 + x])/Abs[-5 + x] <= 2/3, {x}, Reals]
Out[1]= -1 <= x <= 2
Best regards,
Robert
[1] Volker van Nek is the author of solve_rat_ineq
[2] http://thread.gmane.org/gmane.comp.mathematics.maxima.general/7946/