Utilisez la "formule d'Euler" pour trouver la valeur approximative de pi.
Use the following "Euler's formula" to find the approximate value of pi.
π = √{12{1/1^2 - 1/2^2 + 1/3^2 - 1/4^2 + ･･･}}
Let's observe how the approximate value of pi can be obtained as the number of terms increases.