Find the sum of the first 7 terms of the following sequence. Round to the nearest hundredth if necessary.5,6,536,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Q. Find the sum of the first 7 terms of the following sequence. Round to the nearest hundredth if necessary.5,6,536,…Sum of a finite geometric series:Sn=1−ra1−a1rnAnswer:
Identify Sequence Type: First, we need to identify the type of sequence we are dealing with. The given sequence is 5,6,536,…, which suggests that it is a geometric sequence because each term after the first is obtained by multiplying the previous term by a common ratio (r).
Find Common Ratio: To find the common ratio r, we divide the second term by the first term.r=56=1.2
Calculate 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, and r is the common ratio.
Substitute Values: We are looking for the sum of the first 7 terms, so n=7, a1=5, and r=1.2. Plugging these values into the formula, we get:S7=(1−1.2)(5−5×(1.2)7)
Calculate Exponent: Now we calculate (1.2)7 and then substitute it back into the formula.(1.2)7≈3.5832S7=1−1.25−5×3.5832
Simplify Expression: Substitute the value of (1.2)7 into the formula and simplify.S7=1−1.25−5×3.5832S7=−0.25−17.916
Perform Final Calculation: Now we perform the subtraction in the numerator and the division. S7=−0.2−12.916S7≈64.58
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