Math Problem Statement

Si para hallar el área de la región acotada por las curvas se plantea la integral: Determine los valores de c, d, f(y) y el área A.

Solution

The image shows two curves and an enclosed region in the Cartesian plane. The curves are:

  • y=x4y = x - 4
  • x=y22x = y^2 - 2

The objective is to calculate the area of the region enclosed by these curves using integration. The given formula for the area is represented as:

cdm(y)dy\int_c^d m(y) \, dy

where cc and dd are the limits of integration, and m(y)m(y) is a function describing the curve in terms of yy.

Steps to solve:

  1. Find the limits of integration cc and dd: These correspond to the yy-values where the two curves intersect.

    To find the points of intersection, solve the system of equations:

    • y=x4y = x - 4
    • x=y22x = y^2 - 2

    Substitute x=y22x = y^2 - 2 into y=x4y = x - 4:

    y=(y22)4y = (y^2 - 2) - 4 y=y26y = y^2 - 6 y2y6=0y^2 - y - 6 = 0

    Solve the quadratic equation y2y6=0y^2 - y - 6 = 0 using the quadratic formula:

    y=(1)±(1)24(1)(6)2(1)y = \frac{-(-1) \pm \sqrt{(-1)^2 - 4(1)(-6)}}{2(1)} y=1±1+242y = \frac{1 \pm \sqrt{1 + 24}}{2} y=1±252y = \frac{1 \pm \sqrt{25}}{2} y=1±52y = \frac{1 \pm 5}{2} Thus, y=3y = 3 and y=2y = -2 are the limits of integration.

    Therefore, c=2c = -2 and d=3d = 3.

  2. Find the function m(y)m(y): This function represents the difference between the two curves at a given yy-value. Since x=y22x = y^2 - 2 describes the rightmost curve and y=x4y = x - 4 describes the leftmost curve, the function is:

    m(y)=(y22)(y+4)m(y) = (y^2 - 2) - (y + 4) Simplifying: m(y)=y2y6m(y) = y^2 - y - 6

  3. Set up the integral: The area is found by integrating m(y)m(y) from y=2y = -2 to y=3y = 3:

    A=23(y2y6)dyA = \int_{-2}^{3} (y^2 - y - 6) \, dy

  4. Solve the integral: (y2y6)dy=y33y226y\int (y^2 - y - 6) \, dy = \frac{y^3}{3} - \frac{y^2}{2} - 6y Evaluate from y=2y = -2 to y=3y = 3.

Now, let me calculate the area for you.The area of the region enclosed by the curves is 1256\frac{-125}{6}, which corresponds to an absolute value of approximately 20.83 square units (since area is always positive).

Would you like further details on any part of the solution?

Here are five related questions that expand on this concept:

  1. How do you determine which curve represents the upper and lower bounds in a region?
  2. What is the significance of using definite integrals for area calculations?
  3. How can you find the intersection points of more complex curves?
  4. How does the orientation of the curves affect the area calculation?
  5. Can this method be extended to three-dimensional surfaces?

Tip: When finding areas between curves, always ensure that you subtract the lower curve from the upper curve within the integration limits to avoid negative areas.

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Math Problem Analysis

Mathematical Concepts

Integration
Area between curves
Quadratic equations

Formulas

y = x - 4
x = y^2 - 2
Area = \int_c^d m(y) dy
Quadratic formula: y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 10-12