Math 234-Calculus II Summer 2020
Lab 5
This lab is best done during/after homework for Sections 6.5 and 8.1.
1 Directions
Go to https://student.desmos.com and type in this lab's code: 4XB K3E
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Let \[g(x) = \frac{1}{\sqrt{\pi} x},\] defined on \([1,\infty]\).
1.1 Problem 0
Enter your name and SFA email, I need to know who to give the grades to.
1.2 Problem 1
- Define a function \(V\) which outputs the volume of the solid formed by revolving \(g(x)\) about the \(x\)-axis for \(1 \leq x \leq b\).
- Graph the function \(V\). Estimate \(\lim_{b\to \infty} V(b)\) from the graph.
- Verify your answer to 1.2 by evaluating \(V(\infty)\) (type infinity to get \(\infty\)).
1.3 Problem 2
- Define a function \(A\) which outputs the surface area of the surface formed by revolving \(g(x)\) about the \(x\)-axis for \(1 \leq x \leq b\).
- Graph the function \(A\). Estimate \(\lim_{b\to \infty} A(b)\). from the graph.
- Verify your answer to 2.2 by evaluating \(A(\infty)\).
1.4 Problem 3
The surface formed by rotating \(g(x)\) about the \(x\)-axis for \(1 \leq x \leq \infty\) is called Gabriel's Horn. Think of it as a bucket (turn it upright). Suppose the units are liters. What does Problem 1 tell you about how many liters of paint Gabriel's Horn holds? What does Problem 2 tell you about the amount of paint required to paint Gabriel's Horn? What is the problem here?