Math Problem Statement

Simplify the formula given in the image: \( x_m = \frac{m(1 + 2 + \dots + m)}{1^2 + 2^2 + \dots + m^2} \).

Solution

The formula provided in the image is:

xm=m(1+2++m)12+22++m2x_m = \frac{m(1 + 2 + \dots + m)}{1^2 + 2^2 + \dots + m^2}

To simplify and understand this formula:

  1. The numerator involves the sum of the first mm positive integers: 1+2++m=m(m+1)21 + 2 + \dots + m = \frac{m(m+1)}{2}

  2. The denominator involves the sum of the squares of the first mm positive integers: 12+22++m2=m(m+1)(2m+1)61^2 + 2^2 + \dots + m^2 = \frac{m(m+1)(2m+1)}{6}

By substituting these formulas into xmx_m:

xm=mm(m+1)2m(m+1)(2m+1)6x_m = \frac{m \cdot \frac{m(m+1)}{2}}{\frac{m(m+1)(2m+1)}{6}}

Simplify step by step:

  • The numerator becomes: m2(m+1)2\frac{m^2(m+1)}{2}

  • The denominator becomes: m(m+1)(2m+1)6\frac{m(m+1)(2m+1)}{6}

Dividing the two expressions:

xm=m2(m+1)2m(m+1)(2m+1)6x_m = \frac{\frac{m^2(m+1)}{2}}{\frac{m(m+1)(2m+1)}{6}}

Simplify further:

xm=m2(m+1)62m(m+1)(2m+1)x_m = \frac{m^2(m+1) \cdot 6}{2 \cdot m(m+1)(2m+1)}

Cancel common terms:

xm=3m2m+1x_m = \frac{3m}{2m+1}

Final Simplified Formula:

xm=3m2m+1x_m = \frac{3m}{2m+1}


Do you want details about the derivation steps, or do you have any questions?

Here are 5 related questions to explore further:

  1. What is the significance of xmx_m in this formula?
  2. How can this formula be applied to specific problems in mathematics or physics?
  3. What is the behavior of xmx_m as mm \to \infty?
  4. Can you calculate xmx_m for specific small values of mm (e.g., m=1,2,3m = 1, 2, 3)?
  5. How does the simplification process change if higher powers (e.g., cubes) replace squares in the denominator?

Tip:

Always substitute and simplify summation formulas before attempting to directly compute values. It makes the calculations more manageable!

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Math Problem Analysis

Mathematical Concepts

Summation formulas
Simplification of expressions
Fraction simplification

Formulas

Sum of the first n integers: \( 1 + 2 + \dots + n = \frac{n(n+1)}{2} \)
Sum of squares of the first n integers: \( 1^2 + 2^2 + \dots + n^2 = \frac{n(n+1)(2n+1)}{6} \)

Theorems

Arithmetic summation formula
Summation of squares formula

Suitable Grade Level

Grades 10-12