Hello, Some formulas of pi in infinite product: (4/Pi)=product(1/(1-tan(Pi*2^(-n-3))^2),n=0..infinity); (4/Pi)=product((1/2)*(1+1/cos(Pi*2^(-n-2))),n=0..infinity); Pi=2^(n+5/2)*sqrt(1-1/(2^(2^(-n-1))*(product((2-1/(cos(Pi*2^(-n-2)))^2)^(2^(n-1)),n=1..infinity))^(1/2^n))); Pi=2^(n+5/2)*sqrt(1-1/(2^(2^(-n-1))*(product((1-tan(Pi*2^(-n-2))^2)^(2^(n-1)),n=1..infinity))^(1/2^n))); Pi=2^(n+5/2)*sqrt(1-1/(2^(2^(-n-1))*(product(2^(2^(n-1))/(1/cos(Pi*2^(-n-1))+1)^(2^(n-1)),n=1..infinity))^(1/2^n))); Pi/4=sqrt(3*2^(2*n+1)-sqrt(3)*2^(4*n+2)*sqrt(2^(-2^(-n-1)-4*n-1)/(product((1-tan(Pi*2^(-n-2))^2)^(2^(n-1)),n=1..infinity))^(1/2^n)+2^(-4*n-2))); Pi/4=sqrt(3*2^(2*n+1)-sqrt(3)*2^(4*n+2)*sqrt(2^(-2^(-n-1)-4*n-1)/(product((2-1/(cos(Pi*2^(-n-2)))^2)^(2^(n-1)),n=1..infinity))^(1/2^n)+2^(-4*n-2))); 4/Pi=product(((cos((2*Pi)/8^n)+cos(Pi/8^n))*sec((2*Pi)/8^n))/8+(cos((3*Pi)/(2*8^n))*sec((2*Pi)/8^n))/4+((cos(Pi/8^n)+1)*sec((2*Pi)/8^n))/8+(cos(Pi/(2*8^n))*sec((2*Pi)/8^n))/4,n=1..infinity); Best regards.