out aa;
off nat;

s:=solve({
-b*r12/r11 + c -1, 
-c*r21/r22 + b -1},{b,c});

ss:=part(s,1);
b:=rhs(part(ss,1));
c:=rhs(part(ss,2));

a:=-b*r12/r11;
d:=-c*r21/r22;


load "algint";
int(sqrt(1+x**2),x);
int(sqrt(2+x**2),x);
int(sqrt(1+x**4),x);
int(1/sqrt(1+x**4),x);

shut aa;
bye;
end;