Q. Find the value of the following expression and round to the nearest integer:n=2∑3430(1.3)n−2Answer:
Given series and terms: We are given a geometric series with the first term a=30(1.3)2−2=30(1)=30 and a common ratio r=1.3. The sum of a finite geometric series can be found using the formula Sn=(1−r)a(1−rn), where n is the number of terms. First, we need to find the number of terms in the series.
Number of terms calculation: The series starts at n=2 and ends at n=34, so the number of terms is 34−2+1=33. Now we can use the formula for the sum of a geometric series.
Formula for sum of geometric series: Plugging the values into the formula, we get S33=30(1−1.333)/(1−1.3). We need to calculate 1.333 and then proceed with the formula.
Calculate 1.333: Using a calculator, we find that 1.333 is approximately 1425.7631. Now we substitute this value into the formula.
Substitute values into formula: Substituting the values, we get S33=(1−1.3)30(1−1425.7631)=(−0.3)30(−1424.7631). We simplify this to get the sum.
Simplify expression for sum: Simplifying the expression, we get S33=30×1424.7631/0.3. Performing the division and multiplication, we find the sum.
Perform division and multiplication: The sum S33 is approximately 30×4749.2103=142476.309. Now we round this to the nearest integer.
Round sum to nearest integer: Rounding 142476.309 to the nearest integer, we get 142476.
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