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,x³4}}]
> 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, 0£x<4},
> {16 x-x2, x³4}
> }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