Why double integral could calculate area and volume

In summary, an integral can be used to calculate both area and volume depending on the specific context and dimensions given. It is not limited to just one type of measurement and can represent a variety of concepts such as length, probability, etc. depending on the units used.
  • #1
transgalactic
1,395
0
why there are a case where double integral could calculate area
and in other case
it could calculate a volume.

an integral should do only one thing
not both??

for what characteristics it could used to calculate area,
for what its volume
 
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  • #2
Hi transgalactic! :smile:

It depends what you're integrating.

(did you have something specific in mind?)

For example, with an irregular solid you'd probably need 3 integrals, but with say an irregular cylinder (like a cookie-cutter :wink:), all the heights are the same, so you only use 2 integrals . :smile:
 
  • #3
A definite integral (single, double, are whatever) just represents a number. It's only when we give it context by attaching dimensions (e.g., feet, cm, lb) to the quantities involved does it represent area or volume or work or what-have-you.

A single integral could represent an area, volume, length, probability, or any number of other concepts, depending on what we have decided to use for units. It's similar for double integrals.

What makes you think that an integral is supposed to do only one thing?
 

1. How does a double integral calculate area and volume?

Double integrals use the concept of Riemann sums to divide a 2-dimensional region into infinitely small rectangles. By finding the sum of the areas of these rectangles, the double integral can calculate the total area of the region. Similarly, for calculating volume, the double integral divides a 3-dimensional region into infinitely small rectangular prisms and sums their volumes.

2. Why is a double integral needed to calculate area and volume?

A single integral can only calculate the area or volume of a one-dimensional region. However, many real-life objects and scenarios are more complex and require calculations in multiple dimensions. The double integral allows us to calculate the area and volume of 2-dimensional and 3-dimensional objects, respectively.

3. What is the difference between a single integral and a double integral?

A single integral calculates the area under a curve in one dimension, while a double integral calculates the area or volume of a 2-dimensional or 3-dimensional region, respectively. A single integral has one variable of integration, while a double integral has two variables of integration.

4. Can a double integral be used to calculate areas and volumes of irregular shapes?

Yes, a double integral can be used to calculate the area or volume of any 2-dimensional or 3-dimensional shape, including irregular shapes. This is because the integral divides the shape into infinitely small rectangles or prisms, taking into account the variations in width and height.

5. Are there any limitations to using double integrals to calculate areas and volumes?

Double integrals may not be suitable for calculating areas and volumes of infinitely complex or discontinuous shapes. Additionally, the integral may be difficult to evaluate for certain functions, requiring advanced techniques such as change of variables or numerical methods.

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