subsidiary conditions in Solve?
- To: mathgroup at smc.vnet.net
- Subject: [mg17324] subsidiary conditions in Solve?
- From: Sandra McBride <sandra at rgmiller.Stanford.EDU>
- Date: Fri, 30 Apr 1999 23:22:40 -0400
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
I'm trying to solve simultaneous equations, and I'd like to include some
subsidiary conditions which place restrictions on quantities (like the
variance) to be positive. Examples of these conditions are:
2 2
E (M) > (E(M))
and
2
sigma > 0
M
Here's a simple example -- in this case, I'd like to rule out the solution
x=-3. I'm following p. 825, "3.4.9 Solving Equations with Subsidiary
Conditions" of the 1999 Mathematica Book.
In[92]:= subsid1 = Greater[x,0]
Out[92]= x > 0
In[93]:= Solve[x^2 + x - 6 == 0, subsid1]
General::ivar: x > 0 is not a valid variable.
2
Out[93]= Solve[-6 + x + x == 0, x > 0]
What am I doing wrong?