From: didier.oslo@hotmail.com   
      
   On Thursday, 7 November 2013 08:37:00 UTC+1, Albert Rich  wrote:   
   > On Wednesday, November 6, 2013 7:31:17 PM UTC-10, did wrote:   
   >   
   >   
   >   
   > > A possible fix for #66 is:   
   >   
   > >   
   >   
   > > restart:   
   >   
   > > integrand:=(cosh(x)^3 - sinh(x)^3) / (cosh(x)^3 + sinh(x)^3);   
   >   
   > > anti:= -1/(3*(1+tanh(x))) + 4/(3*sqrt(3))*arctan( (2*tanh(x)-1)/sqrt(3));   
   >   
   > > check:=simplify(integrand-diff(anti,x));   
   >   
   > >   
   >   
   > > Did   
   >   
   >   
   >   
   > Yes, that must be what Timofeev intended for the antiderivative of #66, but   
   he got the sign of the first term wrong.   
      
   Note also the cosh^3 instead of cosh^2 in the numerator.   
      
   >   
   > For integrating #69, he is recommending the substitution z=sqrt(tanh(x)),   
   but strangely sqrt(2*tanh(x)) and sqrt(tanh(x)/2) appears in his proposed   
   antiderivative...   
      
   I'll try it when I'll have time for that.   
      
   Did   
      
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