Answer:
(a) Sample mean is 8.639 rad/s
(b) Sample variance is 4.145 rad^2/s^2
(c) Sample standard deviation is 2.036 rad/s
Step-by-step explanation:
(a) Sample mean = 1.375 Hz = 1.375×2π = 1.375×2×3.14159 = 8.639 rad/s
(b) Sample variance = 0.105 Hz^2 = 0.105×(2π)^2 = 0.105×4π^2 = 0.105×4×3.1415^2 = 4.145 rad^2/s^2
(c) Sample standard deviation = 0.324 Hz = 0.324×2π = 0.324×2×3.14159 = 2.036 rad/s
Step-by-step explanation:
in essence, these 2 points are the Hypotenuse of a right-angled triangle. the legs are the coordinate differences between the 2 points creating the 3rd point of that triangle at (-10, 7) : the x coordinate of one point, and the y coordinate of the other.
now, we are looking for the midpoint. this midpoint cuts the original line/hypotenuse in half creating a scaling factor of 1/2.
when we create now a similar triangle based on that "half- Hypotenuse", we need to use the same scaling factor also on the legs (the coordinate differences).
so, when we cut the coordinate differences also in half, we get the coordinates for the midpoint on the main line.
xm, ym are the coordinates of the midpoint.
xm = (x1 + x2)/2 = (-10-3)/2 = -13/2 = -6.5
ym = (y1 + y2)/2 = (-6+7)/2 = 1/2 = 0.5
so, the midpoint is (-6.5, 0.5)
Answer:
4 miles per hour is the speed
Let's say "p" people were going to the expedition initially, and the cost for each was "c", now, we know the total cost is 1800, so for "p", folks that'd be 1800/p how much each one cost, namely, how many times "p" goes into 1800.
well, prior to leaving, 15 dropped out, so that leaves us with " p - 15 ", and the cost "c" bumped up to " c + 27 " for each.

![\bf 1800p=1800(p-15)+27[p(p-15)] \\\\\\ 1800p=1800p-27000+27(p^2-15p) \\\\\\ 0=-27000+27(p^2-15p)\implies 0=-27000+27p^2-405p \\\\\\ \textit{now, let's take a common factor of }27 \\\\\\ 0=p^2-15p-1000\implies 0=(p-40)(p+25)\implies p= \begin{cases} \boxed{40}\\ -25 \end{cases}](https://tex.z-dn.net/?f=%5Cbf%201800p%3D1800%28p-15%29%2B27%5Bp%28p-15%29%5D%0A%5C%5C%5C%5C%5C%5C%0A1800p%3D1800p-27000%2B27%28p%5E2-15p%29%0A%5C%5C%5C%5C%5C%5C%0A0%3D-27000%2B27%28p%5E2-15p%29%5Cimplies%200%3D-27000%2B27p%5E2-405p%0A%5C%5C%5C%5C%5C%5C%0A%5Ctextit%7Bnow%2C%20let%27s%20take%20a%20common%20factor%20of%20%7D27%0A%5C%5C%5C%5C%5C%5C%0A0%3Dp%5E2-15p-1000%5Cimplies%200%3D%28p-40%29%28p%2B25%29%5Cimplies%20p%3D%0A%5Cbegin%7Bcases%7D%0A%5Cboxed%7B40%7D%5C%5C%0A-25%0A%5Cend%7Bcases%7D)
well, you can't have a negative value of people... so it has to be 40.
so, 40 folks were initially going, then 15 dropped out, how many went on the expedition? 40 - 15.