The answer is A.
I hope that helped let me know if i am correct!
Answer:
c = -7
Step-by-step explanation:
0 = -x² + 4x - 7
Compare to
ax² + bx + c
a = -1 , b = 4 , c = -7
The numerical value of the mean voltage is 25.47 V
To find the numerical value of the mean voltage, V of V(t) = 40 sin(t), we integrate V(t) with respect to t over the interval [0.π]
So,
![V = \frac{1}{\pi } \int\limits^\pi _0 {V(t)} \, dt \\V = \frac{1}{\pi } \int\limits^\pi _0 {40sint} \, dt \\V = \frac{1}{\pi } [-40cost]_{0}{\pi } \\V = \frac{1}{\pi } -[40cos\pi - 40cos0]\\\\V = \frac{1}{\pi } (-[40 X (-1) - 40 X 1})\\V = -\frac{1}{\pi } [-40 - 40]\\V = \frac{80}{\pi } \\V = 25.465 V](https://tex.z-dn.net/?f=V%20%3D%20%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20%5Cint%5Climits%5E%5Cpi%20_0%20%7BV%28t%29%7D%20%5C%2C%20dt%20%5C%5CV%20%3D%20%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20%5Cint%5Climits%5E%5Cpi%20_0%20%7B40sint%7D%20%5C%2C%20dt%20%5C%5CV%20%3D%20%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20%5B-40cost%5D_%7B0%7D%7B%5Cpi%20%7D%20%20%5C%5CV%20%3D%20%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20-%5B40cos%5Cpi%20%20-%2040cos0%5D%5C%5C%5C%5CV%20%3D%20%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20%28-%5B40%20X%20%28-1%29%20-%2040%20X%201%7D%29%5C%5CV%20%3D%20-%5Cfrac%7B1%7D%7B%5Cpi%20%7D%20%5B-40%20-%2040%5D%5C%5CV%20%3D%20%5Cfrac%7B80%7D%7B%5Cpi%20%7D%20%5C%5CV%20%3D%2025.465%20V)
V ≅ 25.47 V
So, the numerical value of the mean voltage is 25.47 V
Learn more about mean volatage here:
brainly.com/question/17928028
Answer: the third one down
26 miles times 5,280 feet
Step-by-step explanation:
Look at the units. Miles over miles will cancel, leaving feet... 1 mile is 5,280 feet, because a mile is bigger than a foot, and there are 5,280 feet per 1 mile.