a). Prove that is a function f is harmonic- = 0, then Ldy =0. af b). Using Green's Theorem, evaluate the line integral feh -y dx+ e°% +y ]dy where C =C; +C; is the boundary of the region R that is...

Extracted text: a). Prove that is a function f is harmonic- = 0, then Ldy =0. af b). Using Green's Theorem, evaluate the line integral feh -y dx+ e°% +y ]dy where C =C; +C; is the boundary of the region R that is inside the circle x= 5cos0, y= 5sin0 and outside the eclipse x= 2cos0, y=sin0. c). Find the surface area in the accompanying of the helicoid r(r,0)=(rcos0)i+(rsin0) j + Ok, 0sos2a, Osrsl. (1, 0, 2m) (1, 0, 0),