Page 11 - Module 1 in MATH 1 (Calculus)
P. 11

7. From each corner of a square of tin,                   on a side, small squares of side

                           (in inches) are removed, and the edges are turned up to form an open box

                        (      .    −   ). Express the volume    of the box (in cubic inches) as a function of

                          , and determine the domain of the function.


                        Solution:

                        The box has a square base of side       −        and a height of   . The volume of
                                                                            
                                                          
                        the box is then     =    (     –     )  =      (     −    ) . The domain is the interval
                            <      <    .
                        As      increases  over  its domain,      increases  for  a  time  and  then  decreases
                        thereafter. Thus, among such boxes that may be constructed, there is one of
                        greatest volume, say   . To determine   , it is necessary to locate the precise

                        value of    at which    ceases to increase.


























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