PASCAL用格里高利公式求ππ/4=1-1/3+1/5-1/7……

Question

PASCAL用格里高利公式求π π/4=1-1/3+1/5-1/7……

Answer 1

var
integer i, sign;
real p;
begin
p=0;
sign=1;
for i:=1 to 10000 do
begin
p=p+1/(i*2-1)*sign;
sign=sign*(-1);
end;
p=p*4;
writeln(p);
end.