Use the limit definition of the derivative. A derivative is defined as the rate of change of a function with respect to a variable.

A wire 10 cm long is cut into two pieces, one of length x and the other of length 10 -x. Each is bent in a shape of a square. a) Find a function that models the total area enclosed by the two squares as a function of x. [5 points] b) Find the derivative of the function formed in part (a). [5 points]