1. **State the problem:** Find the average value of the function $f(x) = \sqrt{4 - x^2}$ on the interval $[-2, 2]$.
2. **Formula for average value:** The average value $f_{avg}$ of a continuous function $f(x)$ on $[a,b]$ is given by
$$f_{avg} = \frac{1}{b - a} \int_a^b f(x) \, dx$$
3. **Apply the formula:** Here, $a = -2$ and $b = 2$, so
$$f_{avg} = \frac{1}{2 - (-2)} \int_{-2}^2 \sqrt{4 - x^2} \, dx = \frac{1}{4} \int_{-2}^2 \sqrt{4 - x^2} \, dx$$
4. **Interpret the integral:** The function $f(x) = \sqrt{4 - x^2}$ represents the upper half of a circle with radius 2 centered at the origin.
5. **Calculate the integral:** The integral
$$\int_{-2}^2 \sqrt{4 - x^2} \, dx$$
is the area of the upper semicircle of radius 2.
6. **Area of semicircle:** The area of a full circle is $\pi r^2 = \pi \times 2^2 = 4\pi$.
The area of the upper semicircle is half of that:
$$\frac{1}{2} \times 4\pi = 2\pi$$
7. **Compute average value:** Substitute the integral value back:
$$f_{avg} = \frac{1}{4} \times 2\pi = \frac{2\pi}{4} = \frac{\pi}{2}$$
**Final answer:** The average value of $f(x)$ on $[-2, 2]$ is
$$\boxed{\frac{\pi}{2}}$$
Average Value 62Da81
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