Use the following "Yoshisuke Matsunaga's formula" to find the approximate value of pi.
π = √[9{1 + (1^2)/(3･4) + (1^2･2^2/(3･4･5･6) + (1^2･2^2･3^2)/(3･4･5･6･7･8) + ･･･ )}]
Let's observe how the approximate value of pi can be obtained as the number of terms increases.
You can see that the convergence is very fast.