hello. I would like some direction in how to approach these problems

1.Calculate the line integral

calculated along circle at origin & radius r=pi

2.Find the sum of the fourier series of f(x)= 1 -x on [-pi, pi]

the 1st i tried substituting x+ iy but it looks strange and the parametrization of the line, should I change to polar coordinates? Im trying to use z(t)= a.t + b

the 2nd i set f(x)= 1-sinx which makes it an odd function. but Im not sure how to solve it. like how to get values of n in sin(nt)dt.