Re: very odd failure of Solve
- To: mathgroup at smc.vnet.net
- Subject: [mg131654] Re: very odd failure of Solve
- From: Richard Fateman <fateman at cs.berkeley.edu>
- Date: Mon, 16 Sep 2013 05:15:47 -0400 (EDT)
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On 9/15/2013 4:03 AM, Alan wrote: > 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 *) <snip> Running Reduce[ {%==0}, {x} ] on either equation seems to go into an infinite loop. That maybe be an independent bug, though. I expected that somehow fiddling with the variable names would do something, and that the ordering of a,b,c, alpha was critical. Out of curiosity I tried a few variants to generate a better hypothesis, but ran out of, um, curiosity.