The author thought that Frau Frieda's dreams were a stratagem for surviving because she had revealed about herself that she sold her dreams by foretelling fate about others in the town and had made more fortune out of it. Then she was hired at a salary that covered her minor expenses to predict a religious family's fate at Viennese. So, the author had always thought her dreams were no more than a stratagem for surviving, which never surprised him.
A carpenter needs to make a wooden cuboidal box, closed from all sides, which has a square base and fixed volume. Since he is short of the paint required to paint the box on completion, he wants the surface area to be minimum.
On the basis of the above information, answer the following questions :
Find \( \frac{dS}{dx} \).
