Answer:
i dont know
Step-by-step explanation:
Answer:
a) ![a_n=3\,n-11](https://tex.z-dn.net/?f=a_n%3D3%5C%2Cn-11)
b) ![a_{20}=49](https://tex.z-dn.net/?f=a_%7B20%7D%3D49)
c) term number 17 is the one that gives a value of 40
Step-by-step explanation:
a)
The sequence seems to be arithmetic, and with common difference d = 3.
Notice that when you add 3 units to the first term (-80, you get :
-8 + 3 = -5
and then -5 + 3 = -2 which is the third term.
Then, we can use the general form for the nth term of an arithmetic sequence to find its simplified form:
![a_n=a_1+(n-1)\,d](https://tex.z-dn.net/?f=a_n%3Da_1%2B%28n-1%29%5C%2Cd)
That in our case would give:
![a_n=-8+(n-1)\,(3)\\a_n=-8+3\,n-3\\a_n=3n-11](https://tex.z-dn.net/?f=a_n%3D-8%2B%28n-1%29%5C%2C%283%29%5C%5Ca_n%3D-8%2B3%5C%2Cn-3%5C%5Ca_n%3D3n-11)
b)
Therefore, the term number 20 can be calculated from it:
![a_{20}=3\,(20)-11=60-11=49](https://tex.z-dn.net/?f=a_%7B20%7D%3D3%5C%2C%2820%29-11%3D60-11%3D49)
c) in order to find which term renders 20, we use the general form we found in step a):
![a_n=3\,n-11\\40=3\,n-11\\40+11=3\,n\\51=3\,n\\n=\frac{51}{3} =17](https://tex.z-dn.net/?f=a_n%3D3%5C%2Cn-11%5C%5C40%3D3%5C%2Cn-11%5C%5C40%2B11%3D3%5C%2Cn%5C%5C51%3D3%5C%2Cn%5C%5Cn%3D%5Cfrac%7B51%7D%7B3%7D%20%3D17)
so term number 17 is the one that renders a value of 40
Answer:
B
Step-by-step explanation:
Answer:
54.3329
Step-by-step explanation:
calculator said so lol