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

In summary, the conversation discusses finding the surface area of a revolution about the x-axis for the function y=|x| from x=-2 to x=2. The person asks if they can take the result from x=0 to x=2 and double it, and the other person confirms that it is possible due to the symmetry of the function. There is also a brief mention of a mistake in the attempted solution.
  • #1
Jbreezy
582
0

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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  • #2
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))??
 
  • #3
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
 

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

1. What is meant by "surface area of revolution"?

The surface area of revolution refers to the total area of a three-dimensional figure obtained by rotating a two-dimensional shape around a given axis. This is often used in mathematics and engineering to calculate the surface area of objects such as cones, cylinders, and spheres.

2. How is the surface area of revolution calculated?

The surface area of revolution can be calculated using integral calculus. The formula for calculating the surface area of revolution is 2π∫f(x)√(1+(f'(x))^2)dx, where f(x) is the function defining the shape of the rotated figure and f'(x) is its derivative.

3. What are some real-world applications of the surface area of revolution?

The surface area of revolution has many real-world applications, such as in architecture for calculating the surface area of domes and arches, in manufacturing for determining the amount of material needed to create a curved surface, and in physics for calculating the surface area of objects in motion.

4. How does the shape of the original two-dimensional figure affect the surface area of revolution?

The shape of the original two-dimensional figure has a direct impact on the surface area of revolution. For example, a cylinder with a larger base will have a larger surface area of revolution than one with a smaller base. This is because the shape of the two-dimensional figure determines the curvature and dimensions of the three-dimensional figure.

5. Are there any limitations or challenges when calculating the surface area of revolution?

One limitation when calculating the surface area of revolution is that it can only be applied to objects with rotational symmetry. This means that the shape of the object must be able to be rotated around a given axis without changing. Additionally, the integration required for the calculation can be complex and time-consuming for more intricate shapes.

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