Re: Assigning (really dumb question)
- To: mathgroup at smc.vnet.net
- Subject: [mg61016] Re: Assigning (really dumb question)
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Fri, 7 Oct 2005 03:38:07 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 10/6/05 at 4:08 AM, vjp2.at at at.BioStrategist.dot.dot.com wrote: >What the heck am I doing wrong? I've been away from Mathematica for >a while. >I can't get it to evaluate the expressions at the solved values. >r[q_] := 1800 q - .006 q^2 >c[q_] := 12100000 + 800 q + .004 q ^2 >qa = Solve[ D[ r[q]-c[q] , q] == 0, q] >r[q] /. q -> qa You've asked Mathematica to substitute the replacement rule qa for the variable q after evaluating r[q]. Since Solve returns a list of replacement rules you want to do r[q]/.qa -- To reply via email subtract one hundred and four