omotopy analysis method (HAM) is a promising method for handling func-tional equations. Recent publications proved the eectiveness of HAM in solvingwide variety of problems in dierent elds. HAM has a unique property whichmakes it superior to other analytic methods, this property is its ability to con-trol the convergence region of the solution series. In this work, we claried theadvantages and eects of convergence-control parameter through an example. Manuscript profile