approximation method is the Madhava$-$Leibniz formula$*$:

$={\displaystyle \underset{k=0}{\overset{}{}}}{a}_k=\frac{4}{1}-\frac{4}{3}+\frac{4}{5}-\frac{4}{7}+$dots

where

$a_k=\frac{4(-1{)}^k}{2k+1}$

Write a code to approximate $$ by calculating and adding the first $11$ terms to $k=10)$ of this sequence. Store the result to a variable named plapprox since.