و آر ایل:https://media.cheggcdn.com/study/ecb/ecb46477-ffd7-4309-b3f1-57f2eae4ba95/image
و آر ایل:https://www.chegg.com/homework-help/questions-and-answers/german-mathematician-gottfried-leibniz-developed-following-method-approximate-value-pi-pi--q102126677
