4.1 In aerodynamics and fluid mechanics, the functions u(x, y) and v(x, y) in f(z) where f(z) is analytic, are called the velocity potential and stream function, respectively. u(x,y) = e2*sin(2y) +...

Extracted text: 4.1 In aerodynamics and fluid mechanics, the functions u(x, y) and v(x, y) in f(z) where f(z) is analytic, are called the velocity potential and stream function, respectively. u(x,y) = e2*sin(2y) + 9bxy² – x³, find a) the value of b that satisfy u(x,y) to be a harmonic function, and u(x, y) + i v(x, y). If the function b) the value of f(z) at z = 2 – i.