MathGroup Archive 2002

[Date Index] [Thread Index] [Author Index]

Search the Archive

RE: Why No Solution Using Solve?

  • To: mathgroup at
  • Subject: [mg33911] RE: [mg33902] Why No Solution Using Solve?
  • From: "DrBob" <majort at>
  • Date: Tue, 23 Apr 2002 07:13:20 -0400 (EDT)
  • Reply-to: <drbob at>
  • Sender: owner-wri-mathgroup at

Part of the answer is in the Help for Solve:

"Solve gives generic solutions only.  It discards solutions that are
valid only when the parameters satisfy special conditions. Reduce gives
the complete set of solutions."

The system has no generic solutions.  However, if you specify that Solve
should eliminate {a1, m1} (Solve's third parameter) you get two
solutions, with Cr1 and w in terms of s and the other parameters.

Bobby Treat

-----Original Message-----
From: Tom Compton [mailto:comptont at] 
To: mathgroup at
Subject: [mg33911] [mg33902] Why No Solution Using Solve?

Why doesn't this give a solution?

m1 a1 == P1/ v1 - A1 Rho Cd (v1 + w)^2 /2 - m1 g Cr1 - m1 g S,
m2 a2 == P2/ v2 - A2 Rho Cd (v2 + w)^2 /2 - m2 g Cr1 - m2 g S,
m3 a3 == P3/ v3 - A3 Rho Cd (v3 + w)^2 /2 - m3 g Cr1 - m3 g S},
{Cr1, S, w}

  • Prev by Date: Re: Row vs. Column Vectors (or Matrices)
  • Next by Date: Mathematica Link for Excel - Problems in starting the link
  • Previous by thread: Why No Solution Using Solve?
  • Next by thread: Re: Why No Solution Using Solve?