12.07.2015 Views

Advanced Calculus fi..

Advanced Calculus fi..

Advanced Calculus fi..

SHOW MORE
SHOW LESS
  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Chapter 5 Vector Integral <strong>Calculus</strong> 359(x, JJ) exterior to E. Then v is harmonic as a function of (c, g) in E, so that (5.181)becomesau 1 alog -V'U dc dg =SS t an r anEC- log - - u - logIf, in addition, u is harmonic in E, then (5.182) becomes(5.182)This is valid for (x, y) outside of E.Now for (x, y) interior to E we draw a small circle Cg of radius 6, with centerat (x, y), and let Eg be the region obtained from E by deleting the interior of thiscircle from E (Fig. 5.45). We again take v = log 1 / r and can apply Eq. (5.181) tothe region Eg, since (x, y) is exterior to this region. We obtainOn Cs the normal is exterior to Eg, SO that a/an = -a/&.Thus in polar coordinatesr, 8, with center at (x, y), so that ds = -6 dB on Cs, traced clockwise,rFigure 5.45Proof of third Green identity.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!