If f(x, y) = x3 – 3xy2 of an analytic function f(z) = u + iv, then
1
v is its harmonic conjugate and v(x, y) = 3x2y – y4+ c, c is real constant
2
–v is its harmonic conjugate and v(x, y) = y2 – 3x2 y + c, c is real constant
3
v is its harmonic conjugate and v(x, y) = 3x2y – y4 + c, c is any constant
4
–v is its harmonic conjugate and v(x, y) = y3– 3x2y + c, c is any constant