Construct an analytic function whose real part is ux y x25x
     Construct an analytic function whose real part is u{x, y) = x^2-5xy^2+4y^3  
  
  Solution
u(x,y)=x2-5xy2+4y3
ux=2x-5y2
uxx=2
uy= -10xy+12y2
uyy=-10x+24y
clearly.uxx+uyy 0
i.e.. u is not harmonic..
thus no suvh analytic function exists..

