Double integral (6x^2 -40y)dA

In summary, the problem is to find the double integral of (6x^2-40y)dA over the region D, a triangle with vertices (0,3), (1,1), and (5,3). To divide the region, a picture should be drawn to determine the boundaries. The suggested method is to divide the region at the point (1,1) perpendicular to the x-axis, creating two regions bounded by a constant and a straight line. However, an alternative method is to integrate with respect to y, with the left boundary being the line from (0,3) to (1,1) and the right boundary being the line from (1,1) to (5,3). The equations
  • #1
teng125
416
0
double integral (6x^2 -40y)dA where it is a trianglewith vertices (0,3) , (1,1) and (5,3)

may i know how to divide the region according to this triangle??
 
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  • #2
The fisrt step is to draw a picture. It is then easier to see what needs to be done.

Please provide us with a complete problem statement. What you have posted is not clear.
 
  • #3
∫∫ (for D) (6x^2-40y)dA
,D is the triangle with vertices (0,3), (1,1) and (5,3).

i have drawn the picture
 
  • #4
but i don't know how to divide the region
pls help
 
  • #5
I would divide it at the point (1,1) perpendicularly to the x-axis.
Then the two regions are bounded by a constant and a straight line .
 
  • #6
I wouldn't divide it. I would integrate with respect to y. As y varies from 1 to 3, the left side is the the line from (0,3) to (1,1) and the right boundary is the line from (1,1) to (5,3). What are the equations of those two lines, written as x= ay+ b?
 
  • #7
Even better !
 
  • #8
[What are the equations of those two lines, written as x= ay+ b?]


do u mean we have to formulate another eqn ??or just integrate with respect to the axis coordinate using the eqn given??
 

Related to Double integral (6x^2 -40y)dA

1. What is a double integral?

A double integral is a mathematical concept used in multivariable calculus to calculate the volume under a surface or the area between two surfaces in three-dimensional space.

2. How is a double integral different from a single integral?

A single integral calculates the area under a curve in two-dimensional space, while a double integral calculates the volume under a surface in three-dimensional space.

3. What does the expression (6x^2 - 40y)dA represent in a double integral?

The expression (6x^2 - 40y)dA represents the function being integrated over the specified region, with dA representing the infinitesimal area element.

4. How do you evaluate a double integral?

To evaluate a double integral, you first need to determine the limits of integration for both the inner and outer integrals. Then, you can use various integration techniques such as substitution or integration by parts to solve the integral.

5. What are the practical applications of double integrals?

Double integrals have many practical applications in fields such as physics, engineering, and economics. They can be used to calculate the volume and mass of three-dimensional objects, determine the center of mass of an object, and find the total surface area of a solid.

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