Optimization
Practice
2.1 The Volume of a can is 9π in³. The top and bottom cost twice as much to manufacture as the side. The lateral surface costs 1/4 cent per in². The top and bottom cost 1/2 cent per in². Find the cylinder can of minimum cost.
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2.2 An upside down cone is inscribed in a hemisphere. The radius of the hemisphere is 6 inches. Find the dimensions and volume of the cone of greatest volume.
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2.3 Find the dimensions of the rectangle of the largest area with sides parallel to the coordinate axes that can be inscribed in the region enclosed b the graphs of:
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2.4 Given a right triangle with a hypotenuse of 10cm, let θ = one of the acute angles.
a) For what value of θ (in radians) is the perimeter a maximum?
Let x = side adjacent to θ and let y = side across from θ.
Perimeter = 10 + y + x
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Throw out the
because it is larger than 90 degrees so can’t be in the triangle.
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b) What is the maximum perimeter?
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c) Find the minimum perimeter.
Conceptual: when the triangle is as close to flat as possible. The perimeter will be just over 20cm.
