Math Problem Statement

Cari luas daerah menggunakan integral

Cari luas daerah menggunakan integral

Solution

To find the area of the shaded region bounded by the curves y=x1y = x - 1 and x=3y2x = 3 - y^2, we can set up an integral by determining the points of intersection and integrating the difference of the functions in terms of either xx or yy.

Step-by-Step Solution:

  1. Find the Points of Intersection:

    To find where y=x1y = x - 1 and x=3y2x = 3 - y^2 intersect, substitute y=x1y = x - 1 into x=3y2x = 3 - y^2.

    Substitute: x=3(x1)2x = 3 - (x - 1)^2

    Expand (x1)2(x - 1)^2: x=3(x22x+1)x = 3 - (x^2 - 2x + 1) x=3x2+2x1x = 3 - x^2 + 2x - 1 x23x+2=0x^2 - 3x + 2 = 0 Factor the equation: (x1)(x2)=0(x - 1)(x - 2) = 0 So, x=1x = 1 and x=2x = 2.

    For x=1x = 1: y=11=0y = 1 - 1 = 0 For x=2x = 2: y=21=1y = 2 - 1 = 1

    Therefore, the points of intersection are (1,0)(1, 0) and (2,1)(2, 1).

  2. Set Up the Integral:

    Since we have xx as a function of yy for x=3y2x = 3 - y^2, we can integrate with respect to yy from y=0y = 0 to y=1y = 1.

    The area AA is given by: A=01((y+1)(3y2))dyA = \int_{0}^{1} \left( (y + 1) - (3 - y^2) \right) \, dy Simplify the integrand: A=01(y+13+y2)dyA = \int_{0}^{1} \left( y + 1 - 3 + y^2 \right) \, dy A=01(y2+y2)dyA = \int_{0}^{1} \left( y^2 + y - 2 \right) \, dy

  3. Integrate:

    Integrate each term separately: A=01y2dy+01ydy012dyA = \int_{0}^{1} y^2 \, dy + \int_{0}^{1} y \, dy - \int_{0}^{1} 2 \, dy

    Calculate each integral: 01y2dy=[y33]01=13\int_{0}^{1} y^2 \, dy = \left[ \frac{y^3}{3} \right]_{0}^{1} = \frac{1}{3} 01ydy=[y22]01=12\int_{0}^{1} y \, dy = \left[ \frac{y^2}{2} \right]_{0}^{1} = \frac{1}{2} 012dy=[2y]01=2\int_{0}^{1} 2 \, dy = \left[ 2y \right]_{0}^{1} = 2

    So, A=13+122A = \frac{1}{3} + \frac{1}{2} - 2

    Combine terms: [ A = \frac{1}{3} + \frac{1}{2} - \frac{6}{3} = \frac{1 + 1.5 - 6}{3} = \frac{-3.

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Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Area Between Curves

Formulas

Area = ∫ (Top function - Bottom function) dy

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12