Find the sum of the first 9 terms of the following sequence. Round to the nearest hundredth if necessary.36,9,49,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Q. Find the sum of the first 9 terms of the following sequence. Round to the nearest hundredth if necessary.36,9,49,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Identify Sequence Type: To find the sum of the first 9 terms of the given sequence, we first need to identify the type of sequence. The sequence provided is a geometric sequence because each term is obtained by multiplying the previous term by a common ratio. To find this common ratio (r), we divide the second term by the first term.
Calculate Common Ratio: Calculate the common ratio r:r=369r=41
Use Geometric Series 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.
Find Sum of First 9 Terms: Plug the values into the formula to find the sum of the first 9 terms:S9=1−4136−36×(41)9
Calculate Numerator and Denominator: Calculate the numerator and the denominator separately:Numerator: 36−36×(41)9Denominator: 1−41
Calculate Denominator: Calculate the denominator:Denominator = 1−41=43
Calculate Numerator: Calculate the numerator:Numerator = 36−36×(41)9Since (41)9 is a very small number, we can use a calculator to find its value and then multiply it by 36.
Divide Numerator by Denominator: Using a calculator, we find:(41)9≈0.0000152587890625Numerator =36−36×0.0000152587890625≈36−0.0005488125Numerator ≈35.9994511875
Calculate Final Sum: Now, divide the numerator by the denominator to find the sum:S9=(3/4)35.9994511875S9=35.9994511875×(4/3)
Round to Nearest Hundredth: Calculate the final sum:S9≈35.9994511875×(34)S9≈47.99926825
Round to Nearest Hundredth: Calculate the final sum:S9≈35.9994511875×(4/3)S9≈47.99926825Round the sum to the nearest hundredth:S9≈48.00
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