If an open box is made from a tin sheet 11 in. square by cutting out identical squares from each corner and bending up the resulting flaps, determine the length of the side of the square at each corner that will maximize the volume of the resulting box. Round your answers to two decimal places, if necessary. Let x be the length (in in.) of the side of the square at each corner. X = in. Complete the following parts. (a) Give a function f in the variable x for the quantity to be optimized. f ( x ) = (b) State the domain of this function. (Enter your answer using interval notation.)