Math Problem Statement

The graph of f is given to the right. Evaluate \(\int_{-3}^{3} f(x) \, dx\).

Solution

To evaluate the integral 33f(x)dx\int_{-3}^{3} f(x) \, dx from the graph, we need to calculate the area under the curve from x=3x = -3 to x=3x = 3.

Steps:

  1. Divide the regions: The graph can be divided into three regions from 3-3 to 33:

    • Region 1 (from x=3x = -3 to x=1x = -1): This area is above the x-axis.
    • Region 2 (from x=1x = -1 to x=1x = 1): This area is below the x-axis.
    • Region 3 (from x=1x = 1 to x=3x = 3): This area is above the x-axis.
  2. Calculate the areas of each region:

    • Region 1: This appears to form a triangle with a base of 22 (from x=3x = -3 to x=1x = -1) and a height of 33. The area of a triangle is 12×base×height\frac{1}{2} \times \text{base} \times \text{height}. Area of Region 1=12×2×3=3\text{Area of Region 1} = \frac{1}{2} \times 2 \times 3 = 3
    • Region 2: This is a semicircle with a diameter of 22 (from x=1x = -1 to x=1x = 1) and a radius of 11. The area of a semicircle is 12πr2\frac{1}{2} \pi r^2. Area of Region 2=12π×(1)2=π2\text{Area of Region 2} = \frac{1}{2} \pi \times (1)^2 = \frac{\pi}{2} Since this area is below the x-axis, it is considered negative: Area of Region 2=π2\text{Area of Region 2} = -\frac{\pi}{2}
    • Region 3: This forms another triangle with a base of 22 (from x=1x = 1 to x=3x = 3) and a height of 33. Area of Region 3=12×2×3=3\text{Area of Region 3} = \frac{1}{2} \times 2 \times 3 = 3
  3. Sum the areas: 33f(x)dx=Area of Region 1+Area of Region 2+Area of Region 3=3π2+3\int_{-3}^{3} f(x) \, dx = \text{Area of Region 1} + \text{Area of Region 2} + \text{Area of Region 3} = 3 - \frac{\pi}{2} + 3 33f(x)dx=6π2\int_{-3}^{3} f(x) \, dx = 6 - \frac{\pi}{2}

Final Answer:

33f(x)dx=6π2\int_{-3}^{3} f(x) \, dx = 6 - \frac{\pi}{2}

Would you like further clarification on any of these steps?


Here are some related questions to expand on this topic:

  1. How do we evaluate integrals using different methods, such as Riemann sums?
  2. What is the significance of negative areas in definite integrals?
  3. How do we approximate the area of irregular shapes under curves?
  4. Can definite integrals have applications in physics, such as finding work done?
  5. How do we interpret integrals when the curve crosses the x-axis multiple times?

Tip: When evaluating an integral graphically, always pay attention to whether the areas are above or below the x-axis, as this affects their sign in the integral calculation.

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Math Problem Analysis

Mathematical Concepts

Definite Integrals
Area Under a Curve
Piecewise Areas

Formulas

Area of a triangle = \(\frac{1}{2} \times \text{base} \times \text{height}\)
Area of a semicircle = \(\frac{1}{2} \pi r^2\)

Theorems

Definite Integral Theorem for area calculation

Suitable Grade Level

Grades 11-12