Can You Double the Surface Area Calculation by Symmetry for y=|x|?

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SUMMARY

The surface area of revolution for the function y = |x| from the interval [-2, 2] can be calculated by evaluating the integral from [0, 2] and then doubling the result due to the symmetry of the function around the y-axis. The correct derivative dy/dx for the function is not (5/(2√x)), indicating a misunderstanding in the setup. The integral for the surface area S is given by S = 2 ∏ ∫ 5x^1/2(√(1 + ((5/(2√x))^2))) dx from x = 0 to x = 2, which should be computed before doubling.

PREREQUISITES
  • Understanding of surface area of revolution concepts
  • Familiarity with integral calculus
  • Knowledge of symmetry in functions
  • Ability to compute derivatives
NEXT STEPS
  • Review the calculation of surface area of revolution for different functions
  • Learn about the properties of symmetric functions in calculus
  • Practice solving integrals involving square roots and derivatives
  • Explore the application of the disk method in calculating surface areas
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Students studying calculus, particularly those focusing on integral applications and surface area calculations, as well as educators looking for examples of symmetry in mathematical functions.

Jbreezy
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Homework Statement


I want the surface area of Revolution about x from [-2,2] of y = |x|
So I want to know if I can take it x from [0,2] and just multiply this result by 2?

Homework Equations





The Attempt at a Solution



Set up
dy/dx = (5/(2√x))

S = 2 ∏ ∫ 5x^1/2(√ 1 +((5/(2√x))^2)

from x = 0 , to x = 2. Then multiply this result by 2? Is this OK to do?
 
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Jbreezy said:

Homework Statement


I want the surface area of Revolution about x from [-2,2] of y = |x|
So I want to know if I can take it x from [0,2] and just multiply this result by 2?

Homework Equations


The Attempt at a Solution



Set up
dy/dx = (5/(2√x))

S = 2 ∏ ∫ 5x^1/2(√ 1 +((5/(2√x))^2)

from x = 0 , to x = 2. Then multiply this result by 2? Is this OK to do?

Yes, the function y=|x| is symmetric around the y-axis, so you can double the result from [0,2]. But why do you think dy/dx = (5/(2√x))??
 
Because I;m tired lol and looked off the wrong sheet. My bad. I had this problem done I just didn't know if I could do what I said I didn't see why not though. Thanks,
Later
 

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