very odd failure of Solve
- To: mathgroup at smc.vnet.net
- Subject: [mg131645] very odd failure of Solve
- From: Alan <alan.isaac at gmail.com>
- Date: Sun, 15 Sep 2013 07:08:07 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-outx@smc.vnet.net
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Setting an irrelevant parameter to 0 baffles Solve. Why?
Thanks,
Alan Isaac
$Assumptions =.
ClearAll[f1]
f1[x_] := s*x^\[Alpha] - (a + b + c)*x
Solve[f1[x] == 0, x] (* Solve works *)
Solve[(f1[x] /. {b -> 0}) == 0, x] (* Solve fails *)
(* adding these assumptions does not change things *)
f1assume = (1 > s > 0 && k >= 0 && 1 > \[Alpha] > 0 && a >= 0 && b >= 0 &&
1 > c > 0);
Assuming[f1assume, Solve[f1[x] == 0, x]] (* Solve works *)
Assuming[f1assume, Solve[(f1[x] /. {b -> 0}) == 0, x]] (* Solve fails *)