let A = ρ sinφ a_{ρ} + ρ^{2} a_{φ}evaluate ∮_{L} A.dl for the contour L as show in the figure, please see attachment and guide me in detail. Thanks.
Two legs are straight lines lying on the x-axis. Do you see that the angle $\displaystyle \Phi$ does not change, and only $\displaystyle \rho$, the distance from the origin does? Two of the legs are semi-circles with center at the origin. Do you see that $\displaystyle \rho$, the distance from the origin, does not change and only $\displaystyle \Phi$, the angle, changes?