integration error



Greetings to all -
With maxima 5.29.1 I find the following bug:

(%i1) int1:z*(1-z)*log(1-a^2*z*(1-z));
                                                                2
(%o1)                                                 log(1 - a  z(1 - 
z)) (1 - z) z
(%i2) integrate(int1,z,0,1);
subst: cannot substitute - z for operator z in expression z(1 - z)
  -- an error. To debug this try: debugmode(true);
(%i3) int1:z*(1-z)*log(1-a^2*z*(1-z));
2
(%o3)                                                (1 - z) z log(1 - 
a  (1 - z) z)
(%i4) integrate(int1,z,0,1);
Is  a  positive or negative?

p;
Is  a - 2  positive or negative?

n;
file_search1: trgsmp.mac not found in file_search_maxima,system.
#0: 
trigsimp(?_l=[-(3*a^3*log(abs(a^2*z^2-a^2*z+1))+(12*a^3*z^3-18*a^3*z^2)*log(a^2*z^2-a^2*z+1)+sqrt(4-a^2)*(6*a^2+1...)
  -- an error. To debug this try: debugmode(true);
(%i5)


Many thanks,
Dick Fell

-- 
Richard Noel Fell
Fisher School of Physics
Brandeis University
Waltham, Ma 02454
fell at brandeis.edu
       JMJ