Math Problem Statement

find volume formula including bounds

Find the volume of the solid formed by revolving the curve y = √x from x = 0 to x = 5 around the x-axis.

Solution

The image depicts a 3D solid created by revolving the region under the curve y=xy = \sqrt{x} from x=0x = 0 to x=5x = 5 around the x-axis. To find the volume of the solid, we can use the method of disks.

Volume using the Disk Method:

In this method, the volume of a solid of revolution is computed by integrating the area of infinitesimally thin circular disks along the axis of rotation. The formula for the volume is given by:

V=abπ[f(x)]2dxV = \int_{a}^{b} \pi [f(x)]^2 \, dx

Where:

  • f(x)=xf(x) = \sqrt{x} (the given curve),
  • a=0a = 0 and b=5b = 5 are the limits of integration (bounds).

Step-by-step process:

  1. Curve equation: y=xy = \sqrt{x}.
  2. Disk radius: Since the solid is revolved around the x-axis, the radius of each disk is y=xy = \sqrt{x}.
  3. Disk area: The area of a disk is π×(radius)2=π(x)2=πx\pi \times (\text{radius})^2 = \pi (\sqrt{x})^2 = \pi x.
  4. Volume integral: The total volume is given by the integral of the disk areas from x=0x = 0 to x=5x = 5:

V=05πxdxV = \int_{0}^{5} \pi x \, dx

Solving the integral:

V=π05xdx=π[x22]05=π(522022)V = \pi \int_{0}^{5} x \, dx = \pi \left[ \frac{x^2}{2} \right]_0^5 = \pi \left( \frac{5^2}{2} - \frac{0^2}{2} \right) V=π(252)=25π2V = \pi \left( \frac{25}{2} \right) = \frac{25\pi}{2}

Final Volume:

V=25π2cubic unitsV = \frac{25\pi}{2} \, \text{cubic units}

Thus, the volume of the solid generated by revolving the curve y=xy = \sqrt{x} from x=0x = 0 to x=5x = 5 around the x-axis is 25π2\frac{25\pi}{2} cubic units.

Do you want further details or have any other questions?

Here are 5 relative questions for deeper understanding:

  1. How does the disk method compare to the shell method for calculating volume?
  2. What would change in the formula if we revolved the curve around the y-axis instead of the x-axis?
  3. Can you apply the washer method to this problem if there were another curve?
  4. How would the volume formula change if the curve was y=x2y = x^2 instead?
  5. What are the physical interpretations of this volume in real-world applications?

Tip: Always check the bounds carefully when applying volume formulas to ensure you're integrating over the correct region.

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Math Problem Analysis

Mathematical Concepts

Calculus
Solid of Revolution
Disk Method

Formulas

V = ∫[a,b] π [f(x)]^2 dx
f(x) = √x

Theorems

Disk Method

Suitable Grade Level

Grades 11-12 (Calculus)