Q. Find the value of the following expression and round to the nearest integer:n=2∑5050(1.12)n−2Answer:
Recognize Geometric Series: Recognize that the given expression is a geometric series. A geometric series has the form ∑n=0Narn, where a is the first term, r is the common ratio, and N is the number of terms. In this case, the first term is 50(1.12)0=50, the common ratio r is 1.12, and the series starts at n=2 and goes to n=50.
Adjust Series Starting Point: Adjust the series to start at n=0 for easier calculation. To do this, we can factor out the term (1.12)2 from each term in the series, which gives us 50(1.12)0+50(1.12)1+…+50(1.12)48. Now the series starts at n=0 and goes to n=48.
Use Finite Series Formula: Use the formula for the sum of a finite geometric series, which is S=a(1−rN)/(1−r), where S is the sum of the series, a is the first term, r is the common ratio, and N is the number of terms. Here, a=50, r=1.12, and N=49 (since we start at n=0 and go to n=48, which is S0 terms).
Calculate Sum Formula: Plug the values into the formula to find the sum of the series.S=1−1.1250(1−1.1249)
Calculate 1.1249: Calculate the sum using the values from Step 4.S=50(1−1.1249)/(1−1.12)S=50(1−1.1249)/(−0.12)S=−50(1−1.1249)/0.12
Substitute Value in Formula: Calculate 1.1249 using a calculator to ensure accuracy.1.1249≈289.68 (rounded to two decimal places for simplicity)
Perform Multiplication and Division: Substitute the value from Step 6 into the sum formula.S=−50(1−289.68)/0.12S=−50(−288.68)/0.12
Find Final Sum: Perform the multiplication and division to find the sum.S=50×288.68/0.12S≈50×2405.67S≈120283.33
Round to Nearest Integer: Round the sum to the nearest integer. S≈120283
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