EXPLANATION
 First, let's represent the table with some values of x and y near to the limit:
 x y
 -0.03 0.66 
 -0.02 0.65
 -0.01 0.64
 
 0.01 0.63
 0.02 0.62
 0.03 0.62
Now, we need to plot the function:






The limit is 2/π and it does existe because It's defined at x=0