Find by double integration the area of the region enclosed by curves2 2 2 ,x y a x y a in the first quadrant.
Question
Find by double integration the area of the region enclosed by curves
in the first quadrant.
Solution
To find the area of the region enclosed by the curves, we can use double integration.
First, let's find the points of intersection between the two curves. Setting the equations equal to each other, we have:
x^2 + y^2 = ax + ay
Rearranging the equation, we get:
x^2 - ax + y^2 - ay = 0
Now, we can complete the square for both x and y terms:
(x^2 - ax + a^2/4) + (y^2 - ay + a^2/4) = a^2/2
Simplifying further, we have:
(x - a/2)^2 + (y - a/2)^2 = a^2/2
This equation represents a circle with center (a/2, a/2) and radius sqrt(a^2/2).
To find the points of intersection, we need to solve the equation for x and y. Since we are only interested in the first quadrant, we can set x and y to be positive.
Setting x = a/2 and y = a/2, we get one point of intersection at (a/2, a/2).
Next, we can solve for the other point of intersection by substituting y = a - x into the equation:
x^2 + (a - x)^2 = ax + a(a - x)
Expanding and simplifying, we have:
2x^2 - 2ax + a^2 - ax = 0
Rearranging the equation, we get:
2x^2 - 3ax + a^2 = 0
Using the quadratic formula, we can solve for x:
x = (3a ± sqrt(9a^2 - 8a^2))/4
Simplifying further, we have:
x = (3a ± sqrt(a^2))/4
Since we are only interested in the positive value of x, we have:
x = (3a + a)/4 = a
Therefore, the other point of intersection is (a, 0).
Now, we can set up the double integral to find the area enclosed by the curves. Since the curves are symmetric about the y-axis, we can integrate from y = 0 to y = a/2, and then multiply the result by 2.
The integral is given by:
2 * ∫[0 to a/2] ∫[0 to a] dx dy
Simplifying, we have:
2 * ∫[0 to a/2] a dy
Integrating, we get:
2 * a * [y] [0 to a/2]
Evaluating the integral, we have:
2 * a * (a/2 - 0) = a^2
Therefore, the area of the region enclosed by the curves is a^2.
Similar Questions
Find the area of the region above the x-axis, included between the parabola 𝑦2=𝑎𝑥 and the circle 𝑥2+𝑦2=2𝑎𝑥.
The area of the region lying between the line x – y + 2 = 0, the curve and y-axis, is (in square units)
Find the area between the curves y = x² and y=-2x²-2x. Round to 2 decimal places.
Let the area of the region {(x,y):0≤x≤3,0≤y≤ min{x2+2,2x+2}} be A. Then 12 A is equal to ______
Use a suitable double integral to evaluate the area between the curve y = x2 and the curvey = x where x, y ≥ 0.
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.