Can someone tell me where my calculations are going wrong. I am integrating over C2: (Note Line integral over C1 and C3 are zero.) NOTE: The vector function f(x,y,z) that I am integrating over C2 is highlighted in red in the paint doc. The equation that I am using is: ∫[f (dot) unit tangent]ds Equation of C2: y = 1 - x Parameterization of C2: y = 1 - s and x = s Vector function for C2 is: r(s) = (s,1-s) d(r(s))/ds = (1,-1) Unit d(r(s))/ds = (1,-1)/√2 f(x,y,z) = (y,-x) = (1-s,-s) f (dot) unit tangent = (1-s,-s) dot (1,-1)/√2 = 1/√2 Integrating line integral from 0 to √2 I get: 1/√2(s) from 0 to √2 = 1. The answer is -1.