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reduced functionality of Solve

  • To: mathgroup at
  • Subject: [mg44222] reduced functionality of Solve
  • From: Andrew Collier <colliera at>
  • Date: Wed, 29 Oct 2003 03:34:05 -0500 (EST)
  • Sender: owner-wri-mathgroup at


this may be a naive idea but i expected the functionality of software to
improve with later releases. this, in my opinion, does not seem to be the
case from mathematica 4.1 to 5.0... or maybe i am just missing something.

in a script i have the following bit of code:

F[W_, y_] := Exp[-W(Cos[y]^2/Tp + Sin[y]^2/Tn)]

Tn = 3000;
Tp = 2000;

Solve[{D[F[W, y], y] Tan[y] == 2 F[W, y], W == 1000 Sec[y] ^ 2}, {W, y}];
N[%] // TableForm

now, with mathematica 4.1 this gives:

   Inverse functions are being used. Values may be lost for multivalued

Solve::ifun: Inverse functions are being used by Solve, so some solutions may
     not be found.

Out[5]//TableForm= W -> 7000.   y -> -1.95839

                   W -> 7000.   y -> 1.95839

                   W -> 7000.   y -> -1.1832

                   W -> 7000.   y -> 1.1832

which is useful and the kind of result i am after. however, after
upgrading to mathematica 5.0 the same bit of code gives:

Solve::tdep: The equations appear to involve the variables to be solved for in
    an essentially non-algebraic way.


now i read in the manual that Solve "deals primarily with linear and
polynomial equations", but i would expect that if i got a useful answer
with 4.1 i should get the same (or better!) with 5.0.

is there some way of getting the old behaviour with the newer version of

many thanks and best regards,
andrew collier.

Andrew B. Collier
Antarctic Research Fellow                         tel: +27 31 2601157
Space Physics Research Institute                  fax: +27 31 2616550
University of Natal, Durban, 4041, South Africa

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