/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 A cylindrical-shaped tin can mus... [FREE SOLUTION] | 91Ó°ÊÓ

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A cylindrical-shaped tin can must have a capacity of \(1000 \mathrm{cm}^{3}\) a. Determine the dimensions that require the minimum amount of tin for the can. (Assume no waste material.) According to the marketing department, the smallest can that the market will accept has a diameter of \(6 \mathrm{cm}\) and a height of \(4 \mathrm{cm}\) b. Express your answer for part a. as a ratio of height to diameter. Does this ratio meet the requirements outlined by the marketing department?

Short Answer

Expert verified
The optimal dimensions (radius, height) are \( r = 5.42 \, \mathrm{cm}, h = 10.84 \, \mathrm{cm} \). This doesn't satisfy marketing constraints.

Step by step solution

01

Define Variables and Formulas

Let's start by identifying important variables: Let the radius of the cylinder be \( r \), height be \( h \), and the volume \( V \) be given by \( V = \pi r^2 h \). We know that \( V = 1000 \) and aim to minimize the surface area \( S \, = \; 2\pi r^2 + 2\pi rh \), which includes the top, bottom, and side of the can.
02

Express Height in terms of Radius

Using the volume formula, solve for height in terms of radius: \( h = \frac{1000}{\pi r^2} \). This will allow you to express the surface area solely in terms of \( r \).
03

Substitute Height into Surface Area

Substitute \( h = \frac{1000}{\pi r^2} \) into the surface area equation: \[ S(r) = 2\pi r^2 + 2\pi r\left( \frac{1000}{\pi r^2} \right) \] This simplifies to: \[ S(r) = 2\pi r^2 + \frac{2000}{r} \]
04

Find Critical Points by Differentiation

Differentiate \( S(r) \) with respect to \( r \) and find the critical points: \[ \frac{dS}{dr} = 4\pi r - \frac{2000}{r^2} \] Set the derivative to zero and solve for \( r \): \[ 4\pi r = \frac{2000}{r^2} \rightarrow 4\pi r^3 = 2000 \] Thus, \( r^3 = \frac{500}{\pi} \) and \( r = \left( \frac{500}{\pi} \right)^{1/3} \).
05

Calculate Optimal Dimensions

Evaluate \( h \) using the critical \( r \): \[ r = \left( \frac{500}{\pi} \right)^{1/3} \] \[ h = \frac{1000}{\pi r^2} = 2r \] Simplifying gives \( h = 2 \times \left( \frac{500}{\pi} \right)^{1/3} \).
06

Evaluate If Marketing Conditions Are Met

Calculate the diameter as \( d = 2r \). The minimal \( r \) we've obtained is greater than marketing's minimum acceptable diameter. Determine the ratio \( \frac{h}{d} = \frac{2r}{2r} = 1 \). Thus, it meets the ratio but not necessarily the size.
07

Compare with Marketing Requirements

Check if the calculated diameter \( 2r = 6 \mathrm{cm} \) and height \( 4 \mathrm{cm} \) satisfy marketing criteria. The given dimensions provided by marketing are a constraint, but the optimal \( r \) is derived independently. Make sure we meet the size requirements closely with alternatives if the derived condition isn’t satisfied by the marketing criteria.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Surface Area Minimization
In optimization problems, one of the key tasks is to minimize the surface area of an object while maintaining certain conditions or constraints, like fixed volume or specific dimensions. Here, the problem involves minimizing the surface area of a cylindrical can while keeping its volume constant at 1000 cm³.

To do this, we express the surface area as a function of the radius and height of the cylinder. The formula for the surface area (\(S\)) of a cylinder includes both the curved surface area and the areas of the top and bottom: \[ S = 2\pi r^2 + 2\pi rh \]This represents the top and bottom surfaces (each having an area of \(\pi r^2\)) and the side surface (with an area of \(2\pi rh\)).

To simplify the problem, we find a relationship between the radius (\(r\)) and the height (\(h\)) using the condition that the volume (\(V\)) is fixed: \[ V = \pi r^2 h = 1000 \] Using this, height can be expressed as a function of radius: \[ h = \frac{1000}{\pi r^2} \] By substituting \(h\) in the surface area formula, we reduce the problem to a single variable function, \(S(r)\), allowing us to find its minimum via calculus techniques.
Cylindrical Volume Calculation
Cylindrical volume calculation forms the basis of many real-world applications where uniform stacking or filling is involved. In this problem, the target is to maintain a constant cylindrical volume of 1000 cm³ while optimizing other dimensions like radius and height. The formula for the volume (\(V\)) of a cylinder is:\[V = \pi r^2 h\]Here, \(r\) is the radius, and \(h\) is the height. The problem gives us \(V = 1000\, \text{cm}^3\).

Using this known volume, and rearranging, we expressed the height in terms of the radius:\[h = \frac{1000}{\pi r^2}\]This relationship is critical for other calculations, such as plugging into the surface area equation to minimize surface area.

Keeping this volume constraint ensures that the cylindrical container fulfills its purpose, without having to change the capacity, thus focusing only on reducing the amount of material needed for production.
Critical Point Analysis
Critical point analysis is a vital tool in calculus used to find the points where the function potentially reaches its maximum or minimum values. For our cylinder's surface area (\(S(r)\)), we find the critical points through differentiation. To find critical points, we first differentiate \(S(r)\) with respect to radius (\(r\)):\[\frac{dS}{dr} = 4\pi r - \frac{2000}{r^2}\]We then set \(\frac{dS}{dr} = 0\) to find where the derivative is zero, indicating potential minimums or maximums:\[4\pi r = \frac{2000}{r^2}\]Solving this equation gives us the critical radius value:\[r = \left(\frac{500}{\pi}\right)^{1/3}\]This method ensures that we explore where the surface area function reaches a point of no change, aiding in our search for an optimal size configuration.

After determining the radius, we compute the corresponding height using \(h = \frac{1000}{\pi r^2}\), enabling us to refine our solution to meet both mathematical optimization criteria as well as practical marketing constraints.

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