FUNCTION :  qseries[winquist] - q-series of Winquist's product
    
CALLING SEQUENCE :  winquist(a,b,q,T)
    
PARAMETERS :   a,b,q - names
               T   - positive integer
   
SYNOPSIS :   
   
                                                              T
 winquist(a,b,q,T) returns the q-series expansion to order O(q ) of 
 Winquist's product 
                                                       
                                                                             2  
(a;q)  (q/a;q)  (b;q)  (q/b;q) (ab;q)  (q/(ab);q)  (a/b;q)  (b/(aq);q)  (q;q)  
     oo       oo     oo       oo     oo          oo       oo          oo     oo
   
 where  a,b and q are real or complex variables (or constants) and        
 where  a,b are  nonzero and |q|<1. 
 Here T is postive integer. The expansion is found using Winquist's
 identity. 
   
EXAMPLES :   
   
> winquist(a,b,q,30)/(1-a)/(1-b)/(1-a*b)/(1-a/b):   
   
> normal(series(%,q,30)):   
   
> subs(a=1,b=1,%);   
   
               2       3        4        5        7        8        9         10   
1 - 10 q + 35 q  - 30 q  - 105 q  + 238 q  - 260 q  - 165 q  + 140 q  + 1054 q   
   
            11        12        14         15        16         18         19   
     - 770 q   - 595 q   - 715 q   + 2162 q   + 455 q   - 2380 q   - 1820 q   
   
             20        21         22         23         24         25         26   
     + 2401 q   - 680 q   + 1495 q   + 3080 q   + 1615 q   - 6958 q   - 1925 q   
   
             29      30   
     + 5100 q   + O(q  )   
   
> series(% - tripleprod(q,q^3,10)^10,q,30);   
   
                     30   
                  O(q  )   
   
SEE  ALSO :