Math Problem Statement

Find the volume of the solid generated by rotating the region bounded by the curves y = -x^2 + 7x - 10 and y = 0 about the x-axis.

Solution

The problem is asking to find the volume of the solid generated by rotating the region bounded by the curves:

y=x2+7x10y = -x^2 + 7x - 10 and y=0y = 0

about the x-axis.

Approach:

This type of problem can be solved using the disk method, since we're revolving a region around the x-axis.

The formula for the volume VV of the solid of revolution using the disk method is:

V=πab[f(x)]2dxV = \pi \int_a^b [f(x)]^2 \, dx

where:

  • f(x)f(x) is the function defining the upper curve (in this case, y=x2+7x10y = -x^2 + 7x - 10).
  • [a,b][a, b] are the points where the region is bounded.

Step 1: Find the bounds aa and bb

To determine the bounds, set y=0y = 0 in the equation of the curve y=x2+7x10y = -x^2 + 7x - 10 and solve for xx:

0=x2+7x100 = -x^2 + 7x - 10

Solve this quadratic equation to find the values of xx where the curve intersects the x-axis.

Step 2: Set up the integral

Once the bounds are determined, set up the integral as:

V=πab(x2+7x10)2dxV = \pi \int_a^b (-x^2 + 7x - 10)^2 \, dx

I will now solve for the bounds and compute the volume.The volume of the solid generated by rotating the region bounded by the curves y=x2+7x10y = -x^2 + 7x - 10 and y=0y = 0 about the x-axis is:

V=81π10V = \frac{81\pi}{10}

Would you like further details on the process or have any other questions?

Here are 5 related questions you might find useful:

  1. How is the disk method different from the washer method?
  2. What are the steps to solve for the volume of a solid rotated about the y-axis?
  3. How do you solve a similar problem using cylindrical shells?
  4. Can the same method be applied if the region is rotated about a line other than the x-axis?
  5. What are the conditions for choosing the appropriate method (disk vs washer vs shell)?

Tip: When solving for volumes of revolution, it's crucial to determine the correct bounds from where the curves intersect. Solving the equation for y=0y = 0 is often the first key step.

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Math Problem Analysis

Mathematical Concepts

Calculus
Disk Method
Volume of Solids of Revolution

Formulas

V = π ∫[a,b] [f(x)]^2 dx
Quadratic equation formula ax^2 + bx + c = 0

Theorems

Disk Method
Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12, College Calculus