Math Problem Statement

Evaluate the summation ∑ (3 × 2^(i-1)) from i=1 to 10. Give an exact answer, do not round.

Solution

To solve the given summation:

i=1103×2i1\sum_{i=1}^{10} 3 \times 2^{i-1}

We can factor out the constant 33 from the summation:

3×i=1102i13 \times \sum_{i=1}^{10} 2^{i-1}

This expression is now a geometric series, where the first term a=20=1a = 2^0 = 1 and the common ratio r=2r = 2. The number of terms n=10n = 10.

The sum SnS_n of the first nn terms of a geometric series is given by:

Sn=arn1r1S_n = a \frac{r^n - 1}{r - 1}

Substituting the values:

S10=1×210121=2101S_{10} = 1 \times \frac{2^{10} - 1}{2 - 1} = 2^{10} - 1

Calculate 2102^{10}:

210=10242^{10} = 1024

So,

S10=10241=1023S_{10} = 1024 - 1 = 1023

Thus, the sum of the series is:

3×1023=30693 \times 1023 = 3069

So, the exact answer is 3069\boxed{3069}.

Would you like more details or have any questions?

Here are five related questions to consider:

  1. How would the result change if the summation limit was from i=0i = 0 to i=9i = 9?
  2. What if the common ratio was r=3r = 3 instead of r=2r = 2?
  3. How do you derive the formula for the sum of a geometric series?
  4. What is the effect of multiplying the series by a constant, as done in this problem?
  5. How would you solve this problem if the exponent was i+1i+1 instead of i1i-1?

Tip: When dealing with geometric series, always identify the first term and common ratio before applying the summation formula.

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Math Problem Analysis

Mathematical Concepts

Geometric Series
Algebra
Summation

Formulas

Sum of a geometric series: S_n = a * (r^n - 1) / (r - 1)

Theorems

Geometric Series Theorem

Suitable Grade Level

Grades 9-12