1. The problem statement, all variables and given/known data Using the Arctangent formula pi = 16 * arctan (1 / 5) - 4*arctan(1 / 239) to calculate the value of pi to 53 significant digits. 2. Relevant equations The power series of arctangent(x) is = x − x^3/3 + x^5/5 − x^7/7 + x^9/9...... 3. The attempt at a solution http://tinypic.com/r/fy1tax/5 I attempted this question on MAPLE 13(shown above), but I get an obvious incorrect answer 3.17.... instead of 3.14......... Am i using the formula correctly? I've double checked the values and don't think I missed an exponent or inserted the wrong sign. -Thanks in advance.