Compute the area under the curve

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In summary, the conversation discusses how to compute the area under the curve (x^3+y^3)^2=x^2+y^2, with the additional condition that x>0 and y>0. The solution involves transforming the equation into polar coordinates and then using an integral, resulting in a final answer of 1.87816453805. The conversation also mentions a mistake in the initial calculation, but it is eventually resolved.
  • #1
(@apache@)
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Homework Statement


Hi everyone,
can you give me some hint to solve this? please

Compute the area under the curve:

Homework Equations


[tex](x^3+y^3)^2=x^2+y^2[/tex]

The Attempt at a Solution


I've been trying to transform it into polar coordinates, but I've finished when I get the equation for the radius:
[tex]r^2=1/((\cos(\theta))^3+(\sin(\theta))^3)[/tex],
because then I get the integral which should not be easily integrated (of course I've compute with Jacobian)

thanks for yout attention
 
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  • #2


Have you looked at the graph? It isn't even clear what region the "area under the curve" describes.
 
  • #3


I am sorry, I forgot add this condition: [tex]x>0, y>0[/tex], so then I will get the integral in this case:
[tex]
\int\limits_{0}^{\pi/2}(\int\limits_{0}^{\frac{1}{\sqrt{\cos^3\alpha+\sin^3\alpha}}}r\,dr)\,d\alpha
[/tex],
which results to [tex]1/3 (\pi+2 \sqrt{2} \tanh^{-1}(1/\sqrt{2}))[/tex], but it's little bit different form the correct result which is [tex] \frac{\pi}{6}+\frac{\sqrt{2}}{3}\ln(1+\sqrt{2})[/tex]
 
  • #4


Your integral looks OK but your answer is off by a factor of 1/2. You probably dropped it somewhere in the calculation.
 
  • #5


Yes, you're right. l forget 1/2 in front of integral, then the results are same:
1.8781645380502384306795745680939249649333168829204582775232678988974988081580885734995703727615411934.
Thanks for your time.
 

1. What is the purpose of computing the area under the curve?

The area under the curve is often used to find the total amount or magnitude of a certain variable. It can also be used to compare and analyze data sets.

2. How is the area under the curve calculated?

The area under the curve is calculated by using mathematical methods such as integration or numerical methods such as trapezoidal rule. The specific method used depends on the shape of the curve and the available data points.

3. What types of curves can be used to compute the area under the curve?

The area under the curve can be computed for any continuous curve, including polynomial, exponential, and trigonometric curves. It can also be used for non-linear data sets.

4. What are the applications of computing the area under the curve?

The area under the curve is commonly used in fields such as statistics, physics, economics, and engineering. It can help with data analysis, prediction, and optimization.

5. Are there any limitations to computing the area under the curve?

While computing the area under the curve can provide valuable insights, it is not always an accurate representation of the data. It can also be affected by outliers and the method used for calculation. Additionally, it may not be applicable for discrete data sets.

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