Math Problem Statement

Calcule el área que encierra la gráfica de la función y = (1/2) |x - 4| - 3 y el eje x.

Solution

The problem asks for the area enclosed by the graph of the function y=12x43y = \frac{1}{2} |x - 4| - 3 and the xx-axis.

Let's break down the steps to solve this:

  1. Analyze the function: The function is y=12x43y = \frac{1}{2} |x - 4| - 3, which is a V-shaped absolute value function. The vertex of this function occurs at x=4x = 4 because of the term x4|x - 4|. Plugging x=4x = 4 into the equation gives: y=12443=3y = \frac{1}{2} |4 - 4| - 3 = -3 So, the vertex of the function is at (4,3)(4, -3).

  2. Find the x-intercepts: To determine where the function intersects the xx-axis, set y=0y = 0: 12x43=0\frac{1}{2} |x - 4| - 3 = 0 Solving for x4|x - 4|: 12x4=3\frac{1}{2} |x - 4| = 3 x4=6|x - 4| = 6 This gives two solutions: x4=6x=10x - 4 = 6 \Rightarrow x = 10 x4=6x=2x - 4 = -6 \Rightarrow x = -2 So, the points where the graph intersects the xx-axis are x=2x = -2 and x=10x = 10.

  3. Set up the area integral: The area under the curve from x=2x = -2 to x=10x = 10 is composed of two linear segments due to the absolute value. We can split the integral at x=4x = 4 (the vertex): Area=24(12(4x)3)dx+410(12(x4)3)dx\text{Area} = \int_{-2}^{4} \left( \frac{1}{2} (4 - x) - 3 \right) \, dx + \int_{4}^{10} \left( \frac{1}{2} (x - 4) - 3 \right) \, dx

  4. Evaluate each integral:

    • For 24(12(4x)3)dx\int_{-2}^{4} \left( \frac{1}{2} (4 - x) - 3 \right) \, dx: =24(212x3)dx=24(12x1)dx= \int_{-2}^{4} \left( 2 - \frac{1}{2}x - 3 \right) \, dx = \int_{-2}^{4} \left( -\frac{1}{2}x - 1 \right) \, dx Calculating this integral yields: [14x2x]24=9\left[ -\frac{1}{4}x^2 - x \right]_{-2}^{4} = 9

    • For 410(12(x4)3)dx\int_{4}^{10} \left( \frac{1}{2} (x - 4) - 3 \right) \, dx: =410(12x23)dx=410(12x5)dx= \int_{4}^{10} \left( \frac{1}{2}x - 2 - 3 \right) \, dx = \int_{4}^{10} \left( \frac{1}{2}x - 5 \right) \, dx Calculating this integral yields: [14x25x]410=9\left[ \frac{1}{4}x^2 - 5x \right]_{4}^{10} = 9

  5. Add both areas: Total Area=9+9=18\text{Total Area} = 9 + 9 = 18

Thus, the area enclosed by the graph and the xx-axis is 18u218 \, u^2, which corresponds to option c) 18 u2u^2.

Would you like further details or have any questions?


Here are some related questions to deepen your understanding:

  1. How do you find the vertex of an absolute value function?
  2. Why is the area split into two integrals at x=4x = 4?
  3. How can you determine where a function intersects the x-axis?
  4. What are the steps to solve an absolute value equation like x4=6|x - 4| = 6?
  5. How do you set up and evaluate a definite integral for area calculations?

Tip: For absolute value functions, always locate the vertex to split the integral correctly.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integral
Absolute Value Functions
Area Calculation

Formulas

Area under the curve using definite integrals
Absolute value function y = a|x - h| + k

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

High School (Grades 11-12) or introductory college calculus