Please help with practice example problem 4 and 5.

4) Show that the circu mference of the unit circle is equal to 1 1 2/ d13 (an improper integral} Evaluate, thus verifying that the circumference is 271-. 5) Calculate the Taylor polynomials T2013) and 113(3) centered at a; = a of the function x) = sin a: for the given value of a. {a}a=0 {In} 4" \"2