The first three nonzero terms of the Maclaurin series for the arctangent function are x (1/3)x3+

Question:

The first three nonzero terms of the Maclaurin series for the arctangent function are x − (1/3)x3+ (1/5)x5. Compute the absolute error and relative error in the following approximations of π using the polynomial in place of the arctangent:
a. 4[arctan(1/2) + arctan (1/3)
b. 16 arctan(1/5) − 4 arctan(1/239)