Sqrt Integral Expression 788Ee4
1. **State the problem:**
Calculate the value of
$$\sqrt{\frac{\int_{3\pi/8}^{7\pi/8} 40^2 \, dx}{2\pi} + \frac{\int_{7\pi/8}^{2\pi + 3\pi/8} (-80)^2 \, dx}{2\pi}}$$
2. **Recall the integral of a constant:**
For a constant $c$, $\int_a^b c^2 \, dx = c^2 (b - a)$.
3. **Calculate each integral:**
- First integral:
$$\int_{3\pi/8}^{7\pi/8} 40^2 \, dx = 1600 \times \left(\frac{7\pi}{8} - \frac{3\pi}{8}\right) = 1600 \times \frac{4\pi}{8} = 1600 \times \frac{\pi}{2} = 800\pi$$
- Second integral:
$$\int_{7\pi/8}^{2\pi + 3\pi/8} (-80)^2 \, dx = 6400 \times \left(2\pi + \frac{3\pi}{8} - \frac{7\pi}{8}\right) = 6400 \times \left(2\pi - \frac{4\pi}{8}\right) = 6400 \times \left(2\pi - \frac{\pi}{2}\right) = 6400 \times \frac{3\pi}{2} = 9600\pi$$
4. **Divide each integral by $2\pi$:**
- First term:
$$\frac{800\pi}{2\pi} = 400$$
- Second term:
$$\frac{9600\pi}{2\pi} = 4800$$
5. **Sum the two terms:**
$$400 + 4800 = 5200$$
6. **Take the square root:**
$$\sqrt{5200} = \sqrt{100 \times 52} = 10 \sqrt{52} = 10 \times 2 \sqrt{13} = 20 \sqrt{13}$$
**Final answer:**
$$20 \sqrt{13}$$