Q. Find the value of the following expression and round to the nearest integer:n=2∑25900(1.21)n−1Answer:
Recognize Given Expression: Recognize that the given expression is a geometric series where the first term a=900(1.21)2−1=900(1.21), the common ratio r=1.21, and the number of terms n=25−2+1=24.
Use Formula for Sum: Use the formula for the sum of a finite geometric series, which is Sn=a(1−rn)/(1−r), where Sn is the sum of the first n terms of the geometric series.
Plug Values into Formula: Plug the values into the formula: S24=900(1.21)(1−1.2124)/(1−1.21).
Calculate Numerator: Calculate the numerator of the fraction: 1−1.2124. This requires calculating 1.2124 first.1.2124≈799.53 (using a calculator)Now, subtract this from 1: 1−799.53≈−798.53.
Calculate Denominator: Calculate the denominator of the fraction: 1−1.21=−0.21.
Divide Numerator by Denominator: Now, divide the numerator by the denominator: −798.53/−0.21≈3802.52.
Multiply by First Term: Multiply this result by the first term of the series 900×1.21 to get the sum of the series: 3802.52×900×1.21≈4142712.12.
Round to Nearest Integer: Round the result to the nearest integer: 4142712.12 rounds to 4142712.
More problems from Sum of finite series starts from 1