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Examples from rational function integration.

Consider integrating the following rational function


  > f := (6*x^5+6*x^2-4*x+8*x^3-4)/(x^6+2*x^3-2*x^2+1);
The difficulty in this example is that the denominator does not factor over Q, hence we cannot use the traditional method of splitting the rational function into partial fractions. The Trager-Rothstein algorithm implemented in Maple V yields the nice result That is, there are two logs corresponding to two roots of the polynomial . Hence, Maple obtains

  > int(f,x);
An improvement to this algorithm due to Rioboo is implemented in Release 2. It seeks to obtain a real result from a real integrand with no new poles. For example (note: in Maple V this integral returned complex logs),

  > f := (x^4-3*x^2+6)/(x^6-5*x^4+5*x^2+4);
  > int(f,x);


Klaus Steinberger
Mi Apr 13 10:02:38 MDT 1994