4: (a) Define
f:R->R
by
f(z)=z^(2)
and let
v,w:R^(2)->R
be the real and imaginary parts of
f
so that
f(x+iy)=v(x,y)+iw(x,y)
. Show that
v
and
w
both satisfy Laplace's equation. (b) Solve Dirichlet's problem for
u=u(x,y)
on the square
0<=x<=1,0<=y<=1
satisfying the boundary conditions
u(x,0)=x,u(x,1)=x-1,u(0,y)=-y^(2)
and
u(1,y)=1-y^(2)
. Hint: use
v(x,y)
from Part (a) and notice that
u(x,1)!=v(x,1)
.