1. First, edit the function calculatePi to use the Leibniz formula for pi. The parameter int iterations denotes how many terms we should add. Print the approximation after each iteration.
2. Next, approximate pi by cycling through the loop 7 times (that is, until the last addition is 4/13). What do you get?

3. What's the difference in the approxiamtion you get from running the loop 20 times versus 10 time? (You should only have to make one change to your program to calculate this!)