Find Equal Area Between y=x^2 and y=9

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In summary, to find a horizontal line y=k that divides the area between y=x^2 and y=9 into two equal parts, we need to find the value of k for which the area below the line and above y=x^2 is equal to the area above the line and below y=9. This can be done by finding the two areas as functions of k and setting them equal to each other, or by finding the area of one of the portions and setting it equal to half of the total area.
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mikesown
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Homework Statement


"Find a horizontal line y=k that divides the area between y=x^2 and y=9 into two parts"


Homework Equations





The Attempt at a Solution


Found intersection at (-3,9), (3,9)
Found total area to be 36, half(the area needed for each portion) to be 18. Don't know where to go from here.
 
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  • #2
Find the two areas as a function of k.
 
  • #3
christianjb said:
Find the two areas as a function of k.

Can you elaborate more on that? I'm not quite sure what you mean.
 
  • #4
y=k divides the total area into two parts, A1=A1(k) and A2=A2(k). You need to find an expression for each area as a function of k and then find the value of k for which A1(k)=A2(k)
 
  • #5
Don't be intimidated by the variable k -- the fact it's there changes nothing. You know how to compute areas, so compute the area of one of the portions.
 
  • #6
What is the area of the region bounded by y= k, y= 9 and y= x2? For what value of k is that 18?

Even simpler: What is the area of the region bounded by y= 0, y= k and y= x2? For what value of k is that 18?
 

1. How do you find the area between two curves?

To find the area between two curves, you need to first determine the intersection points of the two curves. Then, you can use integration to find the definite integral of the difference between the two curves over the interval of those intersection points. This will give you the area between the curves.

2. What are the steps to find the equal area between y=x^2 and y=9?

The steps to find the equal area between y=x^2 and y=9 are as follows:
1. Set the two equations equal to each other and solve for x to find the intersection points.
2. Use integration to find the definite integral of the difference between the two curves over the interval of those intersection points.
3. Set this integral equal to half of the total area between the two curves, and solve for x. This will give you the x-values of the bounds for the equal area.
4. Use these x-values to find the y-values and calculate the total area between the curves.
5. Finally, divide the total area by 2 to get the equal area between the two curves.

3. Can you use any method other than integration to find the equal area between two curves?

No, integration is the only method that can accurately find the area between two curves. Other methods, such as geometric approximations, may give an estimate but will not be exact.

4. Is there a shortcut to find the equal area between two curves?

There is no shortcut to find the equal area between two curves. The process involves finding the intersection points, setting up and solving an integral, and then calculating the total area. However, using a graphing calculator or software can make the process easier and quicker.

5. What is the significance of finding the equal area between two curves?

Finding the equal area between two curves can be useful in various applications, such as calculating the work done by a variable force or finding the average value of a function. It can also help with visualizing and understanding the relationship between two functions. Additionally, it is a common problem in calculus and can help strengthen understanding of integration and area under a curve.

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