Q. Find the sum of the first 7 terms of the following series, to the nearest integer.6,29,827,…Answer:
Identify pattern: Identify the pattern of the series. The series starts with 6 and each subsequent term is multiplied by (3/2) to get the next term. This is a geometric series with the first term a=6 and the common ratio r=(3/2).
Use formula for sum: Use the formula for the sum of the first n terms of a geometric series, which is Sn=a(1−rn)/(1−r), where Sn is the sum of the first n terms, a is the first term, r is the common ratio, and n is the number of terms.
Plug in values: Plug in the values for the first 7 terms: a=6, r=23, and n=7. Calculate the sum S7=6(1−(23)7)/(1−23).
Calculate (23)7: Calculate (23)7. This is 2737=1282187.
Substitute in formula: Substitute the value of (23)7 into the sum formula: S7=6(1−1282187)/(1−23).
Simplify expression: Simplify the expression: S7=(−21)6(1−1282187).
Simplify numerator: Simplify the numerator: 1−1282187=(128128)−(1282187)=128128−2187=−1282059.
Substitute numerator: Substitute the simplified numerator into the sum formula: S7=(−1/2)6(−2059/128).
Simplify denominator: Simplify the denominator: −21 is the same as multiplying by −2. So, S7=6(−1282059)×−2.
Multiply terms: Multiply the terms: S7=−12×(−2059/128).
Simplify multiplication: Simplify the multiplication: S7=12824708.
Divide for sum: Divide to find the sum to the nearest integer: S7≈12824708≈193.
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