The sum of the first eight terms of the geometric sequence whose first term is -2.5 and ratio is 2 is: -637.5
The nth term of a geometric sequence is given mathematically as;
T(n) = ar^n
- where, a = first term of the geometric sequence.
- r = common ratio of the sequence
- and n = nth term of the sequence.
Therefore, the sum of the first 8 terms of the geometric sequence is;
- <em>S(8) = a + ar + ar² + ar³ + ar⁴ + ar⁵ + ar⁶ + ar⁷.</em>
In essence;
- since common ratio, r = 2
Therefore, we have;
- S(8) = -2.5(1 + 2 + 2² + 2³ + 2⁴ + 2⁵ + 2⁶ + 2⁷)
S(8) = -637.5.
Therefore, the sum of the first eight terms of the <em>geometric sequence</em> whose first term is -2.5 and ratio is 2 is: -637.5
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Answer:
Do you want it in algebra terms or in geometry terms?
Step-by-step explanation:
In order to determine the number of students surveyed, we will count the number of students in each sub-group.
Students that did not engage: 279
All three behaviours: 90
113 smoked cigrarettes and used illegal drugs:
