Solve'ing piecewise defined functions

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Solve'ing piecewise defined functions*From*: xinwei at otter.stanford.edu (Sha Xin Wei)*Date*: Mon, 18 Apr 94 19:00:59 -0700

What's the state of the M-- art using Solve[{f1[x]==0, ... , fn[x]==0}, x] where fi[] are piecewise linear functions? Simple-minded usage doesn't work: gg[x_] := x + 2 /; x < 0; gg[x_] := x -5 /; x >= 0; Solve[gg[t]==0,t] (-1) {{t -> gg [0]}} nor does resorting to numerics, f = Interpolation[{{-1,1}, {0-$MachineEpsilon,2}, {0, -5}, {1,-4}}, InterpolationOrder->1] Solve[ f[x] == 0, x] (-1) {{x -> InterpolatingFunction[{-1, 1}, <>] [0]}} Xin Wei Stanford