Basic Integral calculus volume problem

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SUMMARY

The discussion focuses on using integral calculus to determine the volume of a solid formed by rotating the area between the curves Y = sqrt(x) + 3 and Y = 7 - (1/2)x around the line Y = 3. The integral setup provided is (π(7 - (1/2)x - 3)² - π(sqrt(x) + 3 - 3)²)dx, with the limits of integration from 0 to 4. This method effectively creates a washer with an outer radius of π(4 - (1/2)x)² and an inner radius of π(x). The approach is confirmed as correct by experienced participants in the forum.

PREREQUISITES
  • Understanding of integral calculus concepts, specifically volume of solids of revolution.
  • Familiarity with the washer method for calculating volumes.
  • Ability to manipulate and solve equations involving square roots and linear functions.
  • Knowledge of setting up definite integrals with appropriate limits.
NEXT STEPS
  • Study the washer method in detail for calculating volumes of solids of revolution.
  • Learn how to derive and set up integrals for different shapes and curves.
  • Explore applications of integral calculus in real-world problems, particularly in physics and engineering.
  • Practice solving similar volume problems using various functions and rotation axes.
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Students and educators in mathematics, particularly those studying calculus, as well as anyone interested in mastering the concepts of volume calculation through integration.

Adam111
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Hi everyone, this is my first time posting on these forums. If I am doing anything wrong, please let me know.


I am having a lot of trouble with conceptualizing rotating lines around the X- and Y-axis.

The problem I am trying to visualize right now is...

Using integrals to represent the volume of the solid formed by...

Y = sqrt(x)+3, Y = 7 - (1/2)x, and the Y-axis. Rotated around the line Y = 3.

my gut feeling for this problem is...

To setup the integral so that it looks like this...

setting the two equations equal, and differentiating for X, the integral is from [0,4]

and this is then my integral setup.

(Pi(7 - (1/2)x - 3)^2 - Pi(sqrt(x) + 3 - 3)^2)DX

This creates a washer with outer radius of Pi(4 - 1/2x)^2 and inner radius Pi(x)


I am pretty new to calculus, and I understand this is a very basic concept.
I am just looking for some pointers on how to approach these kinds of problems.

and is this even a correct way to solve this problem?
 
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