I cant seem to get this problem right:

from what i understand, you solve these with respect to x and y by parametrizing the curve which gets me for the first part r(t)=<sqrt(2)t,0> and r'(t)=<sqrt(2),0>. But when i plug it in as (0) and sqrt(2) for y and dx respectively i only get 0 when i evaluate my integral. the correct answer for C1 should be 1/2, What am i doing wrong? also, i haven't even tried the 2nd or 3rd line integrals yet, but would the arc from the circle be integrated from 0 to pi? Thanks.