Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Find the value of the following expression and round to the nearest integer:

sum_(n=1)^(86)20(1.02)^(n)
Answer:

Find the value of the following expression and round to the nearest integer:\newlinen=18620(1.02)n \sum_{n=1}^{86} 20(1.02)^{n} \newlineAnswer:

Full solution

Q. Find the value of the following expression and round to the nearest integer:\newlinen=18620(1.02)n \sum_{n=1}^{86} 20(1.02)^{n} \newlineAnswer:
  1. Recognize as geometric series: Recognize the sum as a geometric series.\newlineThe general form of a geometric series is n=0Narn\sum_{n=0}^{N} ar^n, where aa is the first term, rr is the common ratio, and NN is the number of terms.\newlineIn this case, a=20(1.02)a = 20(1.02), r=1.02r = 1.02, and N=86N = 86.
  2. Use formula for sum: Use the formula for the sum of a finite geometric series.\newlineThe sum SS of the first NN terms of a geometric series is given by S=a(1rN)/(1r)S = a(1 - r^N) / (1 - r), provided that |r| < 1.\newlineHere, we need to adjust the formula because our series starts at n=1n=1, so we subtract the first term (n=0n=0) from the sum.
  3. Calculate sum using formula: Calculate the sum using the adjusted formula.\newlineS=20(1.02)(1(1.02)86)/(11.02)20(1.02)0S = 20(1.02)(1 - (1.02)^{86}) / (1 - 1.02) - 20(1.02)^0\newlineSince (1.02)0=1(1.02)^0 = 1, we subtract 2020 from the sum.\newlineS=20(1.02)(1(1.02)86)/(0.02)20S = 20(1.02)(1 - (1.02)^{86}) / (-0.02) - 20
  4. Perform calculations: Perform the calculations.\newlineS=20(1.02)(1(1.02)86)/(0.02)20S = 20(1.02)(1 - (1.02)^{86}) / (-0.02) - 20\newlineS=20(1.02)(1(1.02)86)/0.0220S = -20(1.02)(1 - (1.02)^{86}) / 0.02 - 20\newlineS=20(1.02)(1(1.02)86)×5020S = -20(1.02)(1 - (1.02)^{86}) \times 50 - 20\newlineS=20×50×(1.02(1.02)87)20S = -20 \times 50 \times (1.02 - (1.02)^{87}) - 20\newlineS=1000×(1.02(1.02)87)20S = -1000 \times (1.02 - (1.02)^{87}) - 20
  5. Calculate power of 1.02871.02^{87}: Calculate the power of 1.02871.02^{87}. This step involves using a calculator or a computer to find the value of (1.02)87(1.02)^{87}.
  6. Substitute value of 1.02871.02^{87}: Substitute the value of (1.02)87(1.02)^{87} into the sum.\newlineAssuming the value of (1.02)87(1.02)^{87} is calculated correctly, substitute it back into the expression for SS.\newlineS=1000×(1.02(1.02)87)20S = -1000 \times (1.02 - (1.02)^{87}) - 20
  7. Complete calculation and round: Complete the calculation and round to the nearest integer.\newlineAfter finding the exact value of SS, round it to the nearest integer to get the final answer.

More problems from Evaluate definite integrals using the chain rule