RosettaCodeData/Task/Arithmetic-geometric-mean/Zkl/arithmetic-geometric-mean-1.zkl

a:=1.0; g:=1.0/(2.0).sqrt();
while(not a.closeTo(g,1.0e-15)){
   a1:=(a+g)/2.0; g=(a*g).sqrt(); a=a1;
   println(a,"  ",g," ",a-g);
}