Math Problem Statement

integral of x=y^2, x=1-y^2

Solution

The given problem involves solving an integral with respect to the equations:

  1. x=y2x = y^2
  2. x=1y2x = 1 - y^2

We are likely looking for the area between these two curves. To find this area, the steps are as follows:

1. Set the two equations equal to find the points of intersection.

y2=1y2y^2 = 1 - y^2 2y2=12y^2 = 1 y2=12y^2 = \frac{1}{2} y=±12y = \pm \frac{1}{\sqrt{2}}

So, the curves intersect at y=12y = -\frac{1}{\sqrt{2}} and y=12y = \frac{1}{\sqrt{2}}.

2. Set up the integral.

The area between these curves is the difference between the upper function x=1y2x = 1 - y^2 and the lower function x=y2x = y^2 over the range of integration y=12y = -\frac{1}{\sqrt{2}} to y=12y = \frac{1}{\sqrt{2}}.

The area AA is given by: A=1212((1y2)y2)dyA = \int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} \left( (1 - y^2) - y^2 \right) \, dy A=1212(12y2)dyA = \int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} (1 - 2y^2) \, dy

3. Solve the integral.

Break it down into two parts: A=12121dy21212y2dyA = \int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} 1 \, dy - 2 \int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} y^2 \, dy

For the first integral: 12121dy=[y]1212=12(12)=22=2\int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} 1 \, dy = \left[ y \right]_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} = \frac{1}{\sqrt{2}} - \left( -\frac{1}{\sqrt{2}} \right) = \frac{2}{\sqrt{2}} = \sqrt{2}

For the second integral: 1212y2dy=[y33]1212=(12)33(123)=23122=132\int_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} y^2 \, dy = \left[ \frac{y^3}{3} \right]_{-\frac{1}{\sqrt{2}}}^{\frac{1}{\sqrt{2}}} = \frac{\left( \frac{1}{\sqrt{2}} \right)^3}{3} - \left( \frac{-\frac{1}{\sqrt{2}}}{3} \right) = \frac{2}{3} \cdot \frac{1}{2\sqrt{2}} = \frac{1}{3\sqrt{2}}

Thus, the total area is: A=22×132=2232=332232=132A = \sqrt{2} - 2 \times \frac{1}{3\sqrt{2}} = \sqrt{2} - \frac{2}{3\sqrt{2}} = \frac{3}{3\sqrt{2}} - \frac{2}{3\sqrt{2}} = \frac{1}{3\sqrt{2}}

So, the area between the curves is: A=120.707A = \frac{1}{\sqrt{2}} \approx 0.707

Would you like further details, or do you have any questions?

Related questions:

  1. How do we compute areas between more complex curves?
  2. What if the bounds of integration are not symmetric?
  3. Can we use a different method, such as polar coordinates, for similar problems?
  4. How do we find the intersection points for curves of higher degree?
  5. How does this method apply to three-dimensional surfaces?

Tip:

Always check the limits of integration when solving area problems, as curves may have different behaviors across intervals.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integrals
Area Between Curves

Formulas

Integral of the difference between two functions: A = ∫[f(y) - g(y)] dy
Points of intersection: y² = 1 - y²
Solving definite integrals

Theorems

Fundamental Theorem of Calculus
Symmetry in Definite Integrals

Suitable Grade Level

Grades 11-12 and early college