Find the sum of the geometric sequence –3, 15, –75, 375, … when there are 9 terms and select the correct answer below.
2 answers:
Answer:
Answer: A. -976563
Step-by-step explanation:
Sn=sum of the n terms of the geometric sequence.
a= the first term
r=the common ratio
n=numbers of terms.
Sn=a[(1-r^n)/(1-r)]
In this case:
a=-3
r=a₂/a₁=15/-3=-5
n=9
S₉=-3[(1-(-5)⁹) / (1-(-5))=
S₉=-3(1+1953125)/6)=
S₉=-3(1953126/6)=
S₉=-3(325521)
S₉=-976563
Sn=sum of the n terms of the geometric sequence. a= the first term r=the common ratio n=numbers of terms. Sn=a[(1-r^n)/(1-r)] In this case: a=-3 r=a₂/a₁=15/-3=-5 n=9 S₉=-3[(1-(-5)⁹) / (1-(-5))= S₉=-3(1+1953125)/6)= S₉=-3(1953126/6)= S₉=-3(325521) S₉=-976563Answer: A. -976563
You might be interested in
Answer:
???
Step-by-step explanation:
?????what's the question
There would be 9 birds left. 10-1=9
Ok. he jogs 10 laps in a day and each lap is 40 m so 10 times 40 is 400 he jogs 400 meters in a day then multiply that by 5 for the week 400 times 5 is 2000 he jogs 2000 meters each week
The 3 is distributed to the a+b inside the brackets........
Answer:x=4
Step-by-step explanation:
To solve
10(x+1)=56-2(x-1)
Open the brackets
10x+10=56-2x+2
Collect like terms
10x+2x=56-10+2
12x=48
Divide through by 12
x=4