Question for university and i'm very stuck!

A soap film is suspended between two circular hoops of radius a located at x = plusminus b as shown below. The film has rotational symmetry about the x axis with radius given by r= c cosh(x/c). The constant c is determined by the solution to a= c cosh(b/c). Using the correct formula, find the total surface area A of the film.

Any help would be appreciated!