Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Find the sum of the first 7 terms of the following series, to the nearest integer.

6,(9)/(2),(27)/(8),dots
Answer:

Find the sum of the first 77 terms of the following series, to the nearest integer.\newline6,92,278, 6, \frac{9}{2}, \frac{27}{8}, \ldots \newlineAnswer:

Full solution

Q. Find the sum of the first 77 terms of the following series, to the nearest integer.\newline6,92,278, 6, \frac{9}{2}, \frac{27}{8}, \ldots \newlineAnswer:
  1. Identify pattern: Identify the pattern of the series. The series starts with 66 and each subsequent term is multiplied by (3/2)(3/2) to get the next term. This is a geometric series with the first term a=6a = 6 and the common ratio r=(3/2)r = (3/2).
  2. Use formula for sum: Use the formula for the sum of the first nn terms of a geometric series, which is Sn=a(1rn)/(1r)S_n = a(1 - r^n) / (1 - r), where SnS_n is the sum of the first nn terms, aa is the first term, rr is the common ratio, and nn is the number of terms.
  3. Plug in values: Plug in the values for the first 77 terms: a=6a = 6, r=32r = \frac{3}{2}, and n=7n = 7. Calculate the sum S7=6(1(32)7)/(132)S_7 = 6\left(1 - \left(\frac{3}{2}\right)^7\right) / \left(1 - \frac{3}{2}\right).
  4. Calculate (32)7(\frac{3}{2})^7: Calculate (32)7(\frac{3}{2})^7. This is 3727=2187128\frac{3^7}{2^7} = \frac{2187}{128}.
  5. Substitute in formula: Substitute the value of (32)7(\frac{3}{2})^7 into the sum formula: S7=6(12187128)/(132)S_7 = 6(1 - \frac{2187}{128}) / (1 - \frac{3}{2}).
  6. Simplify expression: Simplify the expression: S7=6(12187128)(12).S_7 = \frac{6(1 - \frac{2187}{128})}{(-\frac{1}{2})}.
  7. Simplify numerator: Simplify the numerator: 12187128=(128128)(2187128)=1282187128=2059128.1 - \frac{2187}{128} = \left(\frac{128}{128}\right) - \left(\frac{2187}{128}\right) = \frac{128 - 2187}{128} = -\frac{2059}{128}.
  8. Substitute numerator: Substitute the simplified numerator into the sum formula: S7=6(2059/128)(1/2)S_7 = \frac{6(-2059/128)}{(-1/2)}.
  9. Simplify denominator: Simplify the denominator: 12-\frac{1}{2} is the same as multiplying by 2-2. So, S7=6(2059128)×2S_7 = 6(-\frac{2059}{128}) \times -2.
  10. Multiply terms: Multiply the terms: S7=12×(2059/128)S_7 = -12 \times (-2059/128).
  11. Simplify multiplication: Simplify the multiplication: S7=24708128S_7 = \frac{24708}{128}.
  12. Divide for sum: Divide to find the sum to the nearest integer: S724708128193S_7 \approx \frac{24708}{128} \approx 193.

More problems from Operations with rational exponents