% Session p. 222

r1=3-2*sqrt(2); r2=sqrt(5)+2;      % the Ramanujan-style formula
r3=sqrt(10)-3;r4=5^(1/4)-sqrt(2);
p=2/pi*asin(r1^2*r2^2*r3^2*r4^4)

r1=3+2*sqrt(2); r2=sqrt(5)+2;      % the stabilized formula
r3=sqrt(10)+3;r4=5^(1/4)+sqrt(2);
p=2/pi*asin(1/r1^2/r2^2/r3^2/r4^4)
