Is it worth trying to debug this? I do not see this problem with the
current sources. In fact, I get
log(2*sqrt(2*%i+1)-2*%i-2)+2*acos(2*%i+1)-acos(%i-1)
-log(-2*%i+2*sqrt(4-4*%i)+4)+%pi
-%i*sqrt(2*%i+1)+sqrt(4-4*%i)*%i
And integrate(acos(1+%i*x),x) is
%i*(%i*log(2*sqrt(x^2-2*%i*x)+2*x-2*%i)+sqrt(x^2-2*%i*x))+x
*acos(%i*x+1)
This appears to be correct as the derivative is acos(1+%i*x).
Ray
On Tue, Nov 22, 2011 at 7:36 AM, Richard Fateman
<fateman at eecs.berkeley.edu>wrote:
> On 11/22/2011 7:03 AM, Michel Talon wrote:
>
>> Robert Dodier wrote:
>>
>>> integrate(acos(1+%i*x),x,-1,2)**;
>>>
>> hangs.
>>
>> Indeed i see the same here under sbcl and maxima 5.25.1.
>> I have a backtrace which supports looping always on the same computation:
>>
>>
>> 0: (SB-KERNEL:TWO-ARG-+ -4199579596574115072 -317738973225728000)
>> 1: (CPLUS -4199579596574115072 -317738973225728000)
>> 2: (PCPLUS -317738973225728000 -4199579596574115072)
>> 3: (PPLUS -317738973225728000 -4199579596574115072)
>> 4: (PPLUS1
>> (14 -317738973225728000 10 1470207527488473600 6 -197927315224332800)
>> (14 -4199579596574115072 10 10377946040669729152 6
>> -940439922132963072 2
>>
>> .... snip
>
> It would be most surprising if the bug were in ptimes or pplus, which are
> multiplying and adding polynomials.
>
> One might question how this integration problem was transformed so as to
> need the multiplication
> of polynomials of degrees 44 and 27, repeatedly.
>
>
>
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