Re: Simple question: is it possible to take a derivative and solve for x ?
- To: mathgroup at smc.vnet.net
- Subject: [mg119307] Re: Simple question: is it possible to take a derivative and solve for x ?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Mon, 30 May 2011 06:33:41 -0400 (EDT)
On 5/29/11 at 7:36 AM, t27026t at yahoo.com.br (Alonso) wrote: >I am a beginner, and would like to know if it is possible to solve >for x the first derivative of a long equation in Mathematica. Bear >with me, my background is in Biomedical Sciences. >I am typing the following command: >Solve[D[((x*l1 + (1 - x)*l2)/((x^2*v1 + (1 - x)^2*v2 + 2*x*(1 - >x)*c)^0.5))+((x*L1 + (1 - x)*L2)/((x^2*V1 + (1 - x)^2*V2 + 2*x*(1 - >x)*C)^0.5)), x]==0,x] >But Mathematica 8 simply stops, and no output is given. A portion of the difficulty is likely to be the term 2*x*(1 - x)*C)^0.5) C cannot be used as a variable since it has built-in meaning. Try changing this to a lower case c and see if that helps. It is a good idea to avoid using single upper case letters as variables so as to avoid conflicts with built-in symbols.