If real and imaginary parts of a function of a complex variable are interpreted as velocity potential and stream function, then real and imaginary parts of the kth derivatives are the (k–1) st derivatives of the velocity components in the direction of the real and negative imaginary axis. For slightly cambered profiles that deviate little from the real axis and have the shape of a polynomial of nth order, the imaginary part of the nth derivative of the complex potential is constant in first-order approximation. It is easy to establish such functions of the complex variable in the case of single as well as cascade profiles. Integration then yields the intended results. While there is no continuing need for such a method for single profiles, it is needed for cascades of profiles.