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A very difficult equation ...

• To: mathgroup at smc.vnet.net
• Subject: [mg14063] A very difficult equation ...
• From: tobi.kamke at t-online.de (Julia Kamke)
• Date: Sat, 19 Sep 1998 03:41:59 -0400
• Sender: owner-wri-mathgroup at wolfram.com

Hi!!!


f[x_] := -2 + 2 * Cos[x] + x * Sin[x]

How can I solve the equation f[x] == 0 in a symbolic way? Solve[f[x] ==
0, x] says, that it isn't possible to solve this equation! Furthermore
I can't simplify this equation. But I think, that x = z * 2 * Pi (z =
.. -2, -1, 0, 1, 2 ...) are some of the possible solutions. Is there a
trick or a possibility to find out this solutions and the rest of all
solutions with Mathematica??

Please help me!!!


Thanks,

  Tobi


P. S. Is f[x] == Sin[x](Sin[x](x^2 + 4) - 4x)??? How can I find this out
with Mathematica??