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Integrate problem

  • To: mathgroup at
  • Subject: [mg65493] Integrate problem
  • From: "axman" <yuerlong at>
  • Date: Wed, 5 Apr 2006 06:55:37 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

Hi, Group
    I am new to Mathematica and now meet one problem I can't solve by
self.  First I defined 3 functions: h, f and g

\!\(\(h[t_] := \(-20\)*Cos[t] Exp[\(-t\)\/20];\)\[IndentingNewLine]
  \(f[x_, y_] := Cos[x] Sin[y];\)\[IndentingNewLine]
  \(g[α_, β_, t_] :=
    If[t == 0, \(-1\), If[h[t] <
       β, \(-1\), If[h[t] > α, \(+1\), g[α, β, t - 0.1]]]];\)\)

Now I try to integrate the function f[x,y]*g[x,y,10] on a triangle

      x, y]\ g[x, y, 10]])\) \[DifferentialD]y \[DifferentialD]x\)\)

The output result is strange. How to get correct answer for this

Thank you for help.

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