Iterated Integral Homework: Evaluate I=∫01∫1+y1-y(6y2+10x)dxdy

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In summary, the conversation discusses solving an iterated integral of the form I = \int^{1}_{0}\int^{1+y}_{1-y} (6y^2+ 10x) dxdy. The individual goes through their attempt at a solution, but realizes they made a mistake in substituting limits and corrects it. The final answer is 16.
  • #1
shards5
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Homework Statement


Evaluate the iterated integral I = [tex] \int^{1}_{0}\int^{1+y}_{1-y} (6y^2+ 10x) dxdy [/tex]

Homework Equations



. . . ?

The Attempt at a Solution


Integrate with respect to x gives me the following equation.
[tex] \int^{1}_{0} 6xy^2 + 5x^2 dy [/tex]
I plug in y+1 and y-1 into x and get the following
6y2+12y3+6y4+5+10y+5y2-6y+12y3-6y4-5+10y-5y2
Most of the stuff cancels out giving me
12y3+12y3+10y+10y
which simplifies to
[tex] \int^{1}_{0} 24y^3+20y dy [/tex]
and after integration I get
6y4+10y2
and after plugging in my numbers I get
6+10 = 16 which is wrong. I am not sure where I screwed up.
 
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  • #2
Don't use sup in LaTeX; exponents are indicated by ^, with braces {} if the exponent is more than one character long.

I only briefly looked at your work, but you might want to check your substitution of limits in the first integrand.
 
  • #3
<double post>
 
  • #4
You, were right! I screwed up by substituting the limits into the y instead of x by mistake. Thanks a lot.
 

1. What is an iterated integral?

An iterated integral is a type of double integral, where the outer integral is evaluated with respect to one variable and the inner integral is evaluated with respect to another variable. It is used to find the volume under a surface in a three-dimensional space.

2. How do I evaluate an iterated integral?

To evaluate an iterated integral, you need to first identify the limits of integration for each variable. Then, you can integrate the inner integral with respect to one variable and treat the other variable as a constant. Finally, integrate the outer integral with respect to the other variable, using the result of the inner integral as the integrand.

3. What is the order of integration for an iterated integral?

The order of integration for an iterated integral depends on the shape of the region of integration. If the region is rectangular, the order of integration is usually dx first, then dy. If the region is triangular or has a curved boundary, the order of integration may need to be switched.

4. How do I set up an iterated integral for a given region?

To set up an iterated integral for a given region, you can draw a graph of the region and identify the limits of integration for each variable. You can also use the properties of the region, such as symmetry, to simplify the integral.

5. Can I use an iterated integral to solve real-world problems?

Yes, iterated integrals can be used to solve real-world problems, especially in physics and engineering. They can be used to find the mass, center of mass, and moment of inertia of an object, as well as to calculate work and fluid flow. They can also be used to calculate probabilities in statistics.

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