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Re: Simplification During Integration

  • To: mathgroup at
  • Subject: [mg21407] Re: [mg21391] Simplification During Integration
  • From: Andrzej Kozlowski <andrzej at>
  • Date: Tue, 4 Jan 2000 02:12:38 -0500 (EST)
  • Sender: owner-wri-mathgroup at

This  happen only in rather special cases, usually involving triginometric
functions. If you prefer you can make Mathematica factor out the common
terms, e.g. :

Integrate[Factor[y], t]
      2          g 3            g
Sin[g]  (2 t Cos[-]  Sec[g] Sin[-] -
                 2              2
        g             g 3                 2
    Cos[-] Sec[g] Sin[-]  Sin[2 t]) Tan[g]
        2             2

You can't however in general stop Mathematica transforming the remaining
terms (even those that do not depend on the variable of integration) since
it is often the case that one can  reduce an integral to a form that can be
integrated only by performing such transformations.

> From: Joel Storch <jstorch at>
To: mathgroup at
> Organization: EarthLink Network, Inc.
> Date: Mon, 3 Jan 2000 03:12:24 -0500 (EST)
> To: mathgroup at
> Subject: [mg21407] [mg21391] Simplification During Integration
> In performing a definite or indefinite integral, Mathematica performs
> transformations on parameters which are not dependent upon the variable
> of integration. How do I supress this type of behavior ?
> Example: Consider the two term expression
> y=Tan[g]^2 Sin[g]^3 Cos[t]^2 + Tan[g]^3 Sin[g]^2 Sin[t]^2
> Integrate[y,{t,0,a}] results in an expression in which the
> trigonometric functions of g have been transformed. I would
> expect Mathematica to recognize that these factors are independent of t
> and simply "pull them out" from the integral. Integrating either of the
> terms separately, does not result in these type of transformations.

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