Find the sum of the first 8 terms of the following sequence. Round to the nearest hundredth if necessary.50,44,38.72,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Q. Find the sum of the first 8 terms of the following sequence. Round to the nearest hundredth if necessary.50,44,38.72,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Identify sequence type: To find the sum of the first 8 terms of the given sequence, we first need to identify the type of sequence. We can see that the sequence is decreasing, and each term is a fixed percentage of the previous term, which suggests that it is a geometric sequence. To confirm this, we need to find the common ratio (r) by dividing the second term by the first term.
Calculate common ratio: Calculate the common ratio r by dividing the second term 44 by the first term 50.r=5044r=0.88
Use sum formula: Now that we have the common ratio, we can use the formula for the sum of the first n terms of a geometric series: Sn=1−ra1−a1⋅rn where Sn is the sum of the first n terms, a1 is the first term, r is the common ratio, and n is the number of terms.
Plug values into formula: Plug the values into the formula to find the sum of the first 8 terms.a1=50 (the first term)r=0.88 (the common ratio)n=8 (the number of terms)S8=1−0.8850−50×0.888
Calculate sum: Calculate the sum using the values provided.S8=1−0.8850−50×0.888S8=0.1250−50×0.271S8=0.1250−13.55S8=0.1236.45S8=303.75
Round sum: Round the sum to the nearest hundredth if necessary. In this case, the sum is already at the hundredth place, so no rounding is needed.
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