a,b,c,d = var ('a,b,c,d')
solve([a+b+c*0+d*0 ==0 ,a+b*0+c*0+d == 0,a*0+d*0+b+c == 0,a*0+b*0+c+d == 1],a,b,c,d)

Kreyszig-2.3-13-U (last edited 2010-12-17 09:25:41 by harsha)