The amount of passwords possible is:
![{8}^{6} = 262144](https://tex.z-dn.net/?f=%20%7B8%7D%5E%7B6%7D%20%20%3D%20262144)
Since he only tries once for the first try we get:
![{262144}^{ - 1}](https://tex.z-dn.net/?f=%20%7B262144%7D%5E%7B%20-%201%7D%20)
Thus there is a:
![0.0001\%](https://tex.z-dn.net/?f=0.0001%5C%25)
Chance he will guess the password on his first try.
Answer:about 22.3km2
Step-by-step explanation:
Radius = 5.33/2 =
Area = πr2 = 3.142*2.665^2
= 22.3 km2
Approximately 22km2
I assume you mean to ask how to find the sum of the seven terms?
You have
![a_2=ra_1](https://tex.z-dn.net/?f=a_2%3Dra_1)
![a_3=ra_2=r^2a_1](https://tex.z-dn.net/?f=a_3%3Dra_2%3Dr%5E2a_1)
![a_4=ra_3=r^3a_1](https://tex.z-dn.net/?f=a_4%3Dra_3%3Dr%5E3a_1)
...
![a_7=ra_6=r^6a_1](https://tex.z-dn.net/?f=a_7%3Dra_6%3Dr%5E6a_1)
So the sum is
![a_1+ra_1+r^2a_1+\cdots+r^6a_1=a_1(1+r+r^2+\cdots+r^6)=a_1\times\dfrac{1-r^7}{1-r}](https://tex.z-dn.net/?f=a_1%2Bra_1%2Br%5E2a_1%2B%5Ccdots%2Br%5E6a_1%3Da_1%281%2Br%2Br%5E2%2B%5Ccdots%2Br%5E6%29%3Da_1%5Ctimes%5Cdfrac%7B1-r%5E7%7D%7B1-r%7D)
You know that
![a_1=-11](https://tex.z-dn.net/?f=a_1%3D-11)
and
![r=-4](https://tex.z-dn.net/?f=r%3D-4)
, so the sum is equal to
Picture?? This question is incomplete just get a picture then I can answer it