Re: Solve and Piecewise Functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg76435] Re: Solve and Piecewise Functions*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Tue, 22 May 2007 02:49:44 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <f2rqtl$9u1$1@smc.vnet.net>

Michael Madrid wrote: > I was hoping something like this: > > > Clear["*"] > g=Piecewise[{{0,x<0},{2 x-x^2,0<=x<4},{16 x-x^2,xÂ³4}}] > h=x-2; > Solve[gÅ h,x] > > > would give me a meaningful answer. But all I get is this: > > > Solve[\[Piecewise]{ > {0, x<0}, > {2 x-x2, 0Â£x<4}, > {16 x-x2, xÂ³4} > }Å -2+x,x] > > Any thoughts on how to do this? > Use Reduce rather than Solve. In[1]:= Clear["Global`*"] g[x_] = Piecewise[{{0, x < 0}, {2*x - x^2, Inequality[0, LessEqual, x, Less, 4]}}, 16*x - x^2]; h[x_] = x - 2; Reduce[g[x] == h[x], x] Out[4]= x == 2 || x == (1/2)*(15 + Sqrt[233]) Regards, Jean-Marc