Math Problem Statement

Find the closest integer of \( \frac{2023 \times 2024 \times 2025}{1^2 + 3^2 + 5^2 + \ldots + 2021^2 + 2023^2} \).

Solution

The question involves finding the closest integer to the expression:

2023×2024×202512+32+52++20212+20232.\frac{2023 \times 2024 \times 2025}{1^2 + 3^2 + 5^2 + \ldots + 2021^2 + 2023^2}.

Step 1: Simplify the denominator

The denominator is the sum of squares of odd integers from 121^2 to 202322023^2. This sequence is:

12,32,52,,20232.1^2, 3^2, 5^2, \ldots, 2023^2.

This sequence has the general form (2k1)2(2k-1)^2, where k=1,2,,nk = 1, 2, \ldots, n, and nn is the number of odd integers up to 2023. Since the odd integers are spaced by 2, nn is given by:

n=202312+1=1012.n = \frac{2023 - 1}{2} + 1 = 1012.

Thus, the sum of squares of the first nn odd integers is:

S=k=1n(2k1)2.S = \sum_{k=1}^n (2k-1)^2.

Using the formula for the sum of squares of odd numbers:

k=1n(2k1)2=n(2n1)(2n+1)3.\sum_{k=1}^n (2k-1)^2 = \frac{n(2n-1)(2n+1)}{3}.

Substituting n=1012n = 1012:

k=11012(2k1)2=1012202320253.\sum_{k=1}^{1012} (2k-1)^2 = \frac{1012 \cdot 2023 \cdot 2025}{3}.

Thus, the denominator is:

1012202320253.\frac{1012 \cdot 2023 \cdot 2025}{3}.

Step 2: Simplify the fraction

The numerator of the fraction is 2023×2024×20252023 \times 2024 \times 2025. The fraction becomes:

2023×2024×20251012202320253.\frac{2023 \times 2024 \times 2025}{\frac{1012 \cdot 2023 \cdot 2025}{3}}.

Cancel 20232023 and 20252025 from the numerator and denominator:

=202431012.= \frac{2024 \cdot 3}{1012}.

Simplify further:

=202410123=23=6.= \frac{2024}{1012} \cdot 3 = 2 \cdot 3 = 6.

Step 3: Conclusion

The closest integer to the given expression is:

6.\boxed{6}.

Would you like a detailed breakdown of any of the steps?


Related Questions:

  1. How is the formula for the sum of squares of odd integers derived?
  2. What is the general formula for the sum of squares of the first nn integers?
  3. How would the calculation change if the sequence included even integers as well?
  4. Can you calculate the exact numerical value for 2023×2024×202512+32++20232\frac{2023 \times 2024 \times 2025}{1^2 + 3^2 + \ldots + 2023^2} using a calculator?
  5. How does this problem generalize to sequences of squares of integers other than odd integers?

Tip:

When dealing with sequences, always check for a formula that simplifies the summation, especially for arithmetic or geometric progressions!

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Math Problem Analysis

Mathematical Concepts

Sequences and Series
Sum of Squares
Simplification of Rational Expressions

Formulas

Sum of squares of the first n odd integers: \( \sum_{k=1}^n (2k-1)^2 = \frac{n(2n-1)(2n+1)}{3} \)

Theorems

Arithmetic progression of odd numbers
Simplification techniques for rational fractions

Suitable Grade Level

Grades 10-12