document.write( "Question 549580: A piece of wire 16 cm long is cut into two pieces, with the first piece having length x. The first piece is formed into a rectangle in which the length is twice the width. The second piece of wire is also formed into a rectangle, but with the length three times the width. For what value of x is the total area of the two rectangles a minimum? \n" ); document.write( "
Algebra.Com's Answer #357888 by solver91311(24713)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "From which we can derive:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Likewise, since the perimeter of the other rectangle is \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "From which we can derive:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The area of the first rectangle in terms of its width:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "And the area of the second rectangle in terms of its width is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then the total area is given by:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Substituting the earlier derived expressions for \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If you expand, collect terms, and find a common denominator, you will have a function that is a quadratic trinomial with a positive lead coefficient, i.e. the equation of a convex up parabola.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If this is an algebra problem, use the formula for the \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If this is a calculus problem, take the first derivative and set it equal to zero. Solve the resulting equation. Verify that the second derivative evaluates to a positive number at this value of the independent variable.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "John \n" ); document.write( " \n" ); document.write( "My calculator said it, I believe it, that settles it \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |