The function z = f (x, y) is said to satisfy Laplace’s equation if z_xx + z_yy = 0. Functions that satisfy such an equation play an important role in a variety of applications in the physical sciences, especially in the theory of electricity and magnetism. In Exercises 73 through 76, determine whether the given function satisfies Laplace’s equation.

z = [(x − 1)² + (y + 3)²]^−1/2