39.65 is the approximate value of arccos0.77
Answer:
The estimated mean number of rockets hits in the region is 533.
Step-by-step explanation:
We are given the following information,
Number of rocket hits | Observed number of regions
0 | 228
1 | 214
2 | 94
3 | 32
4 | 7
5 | 0
6 | 0
7 | 1
We are asked to estimate the mean number of rocket hits in the region.
The mean or expected value is given by

Therefore, the mean number of rockets hits in the region is 533.
I was never sure of what the "additive inverse" is.
So, just now, just for you, I went and looked it up.
The additive inverse of any number ' A ' is the number
that you need to ADD to A to get zero. That's all !
So now, let's check out the choices:
a), 6, -(-6)
That second number, -(-6), is the same as +6 .
So the two numbers are the same.
Do you get zero when you add them up ? No.
b). -7, 7
What do you get when you add -7 and 7 ?
You get zero.
So these ARE additive inverses.
c). -7, -7
What do you get when you add -7 to -7 ?
You get -14 . That's not zero, so these
are NOT additive inverses.
d). 7, 7
What do you get when you add 7 to 7 ?
You get 14. That's NOT zero, so these
are NOT additive inverses.
e). 6, -6
What do you get when you add 6 to -6 ?
You get zero.
So these ARE additive inverses.
What do we end up with from the list of choices:
a)., c)., and d). are NOT additive inverses.
b). and e). ARE additive inverses.
The answer is C. 680 is the initial value and 4.3 is the growth rate.