Math Problem Statement

Find the volume of the solid whose base is the region bounded by the curves 1x = y^2, 2x = y^2, x = 4 in the first quadrant, and whose cross-sections taken perpendicular to the x-axis are squares.

Solution

This problem involves finding the volume of a solid formed by square cross-sections taken perpendicular to the xx-axis.

Step 1: Analyze the Problem

The solid's base is the region in the first quadrant bounded by the curves: 1x=y2,2x=y2,x=4.1x = y^2, \quad 2x = y^2, \quad x = 4. From these equations:

  • x=y2x = y^2 and y2=2xy^2 = 2x give the bounds for y2y^2.
  • The region is further restricted by x=4x = 4, setting the upper limit.

Step 2: Set up the Geometry of the Squares

The side length of each square is determined by the distance between the curves: Side length=2xx.\text{Side length} = \sqrt{2x} - \sqrt{x}. The area of the square is then: Area=(2xx)2.\text{Area} = \left(\sqrt{2x} - \sqrt{x}\right)^2.

Step 3: Integrate to Find the Volume

The volume is the integral of the cross-sectional area along the xx-axis, from x=0x = 0 (where the curves intersect) to x=4x = 4: V=04(2xx)2dx.V = \int_{0}^{4} \left(\sqrt{2x} - \sqrt{x}\right)^2 \, dx.

Step 4: Expand the Square

Expanding (2xx)2\left(\sqrt{2x} - \sqrt{x}\right)^2: (2xx)2=2x2x3/2+x.\left(\sqrt{2x} - \sqrt{x}\right)^2 = 2x - 2x^{3/2} + x.

Thus, the volume integral becomes: V=04(2x2x3/2+x)dx.V = \int_{0}^{4} \left(2x - 2x^{3/2} + x\right) \, dx.

Step 5: Integrate Term by Term

Integrate each term:

  1. 2xdx=x2\int 2x \, dx = x^2,
  2. 2x3/2dx=45x5/2\int -2x^{3/2} \, dx = -\frac{4}{5}x^{5/2},
  3. xdx=12x2\int x \, dx = \frac{1}{2}x^2.

Combining these: V=[x245x5/2+12x2]04.V = \left[x^2 - \frac{4}{5}x^{5/2} + \frac{1}{2}x^2\right]_{0}^{4}.

Step 6: Evaluate the Integral

At x=4x = 4: x2=16,45x5/2=4532=1285,12x2=8.x^2 = 16, \quad \frac{4}{5}x^{5/2} = \frac{4}{5} \cdot 32 = \frac{128}{5}, \quad \frac{1}{2}x^2 = 8. Thus: V=16+81285=241285=12051285=85.V = 16 + 8 - \frac{128}{5} = 24 - \frac{128}{5} = \frac{120}{5} - \frac{128}{5} = -\frac{8}{5}.

Would you like me to double-check interpretations? I could . Other? or parameter

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Volume of Solids
Cross-Sectional Area

Formulas

Volume = ∫[a, b] (cross-sectional area) dx
Side length of square = sqrt(2x) - sqrt(x)
Area of square = (side length)^2

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Undergraduate Calculus (College Level)