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|    sci.math.symbolic    |    Symbolic algebra discussion    |    10,432 messages    |
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|    Message 9,419 of 10,432    |
|    clicliclic@freenet.de to Albert Rich    |
|    Re: Integrate[ArcTanh[t] Log[t]/(t - 1),    |
|    28 Apr 17 23:05:30    |
      Albert Rich schrieb:       >       > What Rubi needs to know is how to derive it.       >              Here are some relations for the specific original problem, to be broken       down further:              INT(LOG(x)*LOG(1 + x)/(x - 1), x)        = LOG(1 - x)*LOG(x)*LOG(1 + x)        + LOG(1 + x)*polylog(2, x)        - polylog(3, x)        - polylog(3, 1 + 1/x)        - INT(LOG(x)*LOG(1 - x)/(x + 1), x)        + INT(polylog(2, x)/(x*(x + 1)), x)        - INT(polylog(2, 1 + 1/x)/(x*(x + 1)), x)              - INT(LOG(x)*LOG(1 - x)/(x + 1), x)        = - LOG(2)*LOG(x)*LOG((1 + x)/2)        + 1/2*LOG(2)*LOG((1 + x)/2)^2        + LOG(x)*polylog(2, (1 + x)/2)        - polylog(3, (1 + x)/2)        + INT(LOG(2)*LOG((x + 1)/2)/(x*(x + 1)), x)        - INT(polylog(2, (x + 1)/2)/(x*(x + 1)), x)              INT(polylog(2, x)/(x*(x + 1)), x)        - INT(polylog(2, 1 + 1/x)/(x*(x + 1)), x)        = - LOG(2)*LOG((1 + x)/2)*LOG((1 + x)/(2*x))        + 1/2*LOG(1 - x)*LOG((1 + x)/(2*x))^2        + 1/2*LOG(- 1/x)*LOG((1 + x)/(2*x))^2        - 1/2*LOG((-1 + x)/(2*x))*LOG((1 + x)/(2*x))^2        + LOG((1 + x)/(2*x))*polylog(2, 1 + 1/x)        - LOG((1 + x)/(2*x))*polylog(2, x)        + LOG((1 + x)/(2*x))*polylog(2, (1 + x)/2)        - LOG((1 + x)/(2*x))*polylog(2, (1 + x)/(2*x))        + polylog(3, (1 + x)/(2*x))        - INT(LOG(2)*LOG((x + 1)/2)/(x*(x + 1)), x)        + INT(polylog(2, (x + 1)/2)/(x*(x + 1)), x)              The final two integrals drop out. Still, his may be hard to cast into a       sequence of goal-directed rewrite rules. Perhaps Rubi should adopt the       generic Mathematica antiderivative wholesale?              Martin.              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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