Lesson 16
Minimizing Surface Area
Problem 1
There are many cylinders with a volume of \(144\pi\) cubic inches. The height \(h(r)\) in inches of one of these cylinders is a function of its radius \(r\) in inches where \(h(r)=\frac{144}{r^2}\).
- What is the height of one of these cylinders if its radius is 2 inches?
- What is the height of one of these cylinders if its radius is 3 inches?
- What is the height of one of these cylinders if its radius is 6 inches?
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
Problem 2
The surface area \(S(r)\) in square units of a cylinder with a volume of 18 cubic units is a function of its radius \(r\) in units where \(S(r)=2\pi r^2+\frac{36}{r}\). What is the surface area of a cylinder with a volume of 18 cubic units and a radius of 3 units?
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
Problem 3
Han finds an expression for \(S(r) \) that gives the surface area in square inches of any cylindrical can with a specific fixed volume, in terms of its radius \(r\) in inches. This is the graph Han gets if he allows \(r\) to take on any value between -1 and 5.
- What would be a more appropriate domain for Han to use instead?
- What is the approximate minimum surface area for the can?
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
Problem 4
The graph of a polynomial function \(f\) is shown. Is the degree of the polynomial even or odd? Explain your reasoning.
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
(From Unit 2, Lesson 8.)Problem 5
The polynomial function \(p(x)=x^4+4x^3-7x^2-22x+24\) has known factors of \((x+4)\) and \((x-1)\).
- Rewrite \(p(x)\) as the product of linear factors.
- Draw a rough sketch of the graph of the function.
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
(From Unit 2, Lesson 12.)Problem 6
Which polynomial has \((x+1)\) as a factor?
\(x^3+2x^2-19x-20\)
\(x^3-21x+20\)
\(x^3+8x+11x-20\)
\(x^3-3x^2+3x-1\)
Solution
Teachers with a valid work email address can click here to register or sign in for free access to Formatted Solution.
(From Unit 2, Lesson 15.)