Math Problem Statement

Expand 1/(1-x)^(3n+3)

Solution

To expand 1(1x)3n+3\frac{1}{(1 - x)^{3n + 3}}, we can apply the binomial series expansion for expressions of the form (1x)k(1 - x)^{-k}, where kk is a positive integer or a real number.

The binomial series expansion for (1x)k(1 - x)^{-k} is given by:

(1x)k=m=0(k+m1m)xm(1 - x)^{-k} = \sum_{m=0}^{\infty} \binom{k+m-1}{m} x^m

In this case, we have k=3n+3k = 3n + 3, so the expansion becomes:

1(1x)3n+3=m=0(3n+3+m1m)xm\frac{1}{(1 - x)^{3n+3}} = \sum_{m=0}^{\infty} \binom{3n+3+m-1}{m} x^m

Step-by-step expansion:

  1. The general term of the expansion is:

    Term=(3n+2+mm)xm\text{Term} = \binom{3n+2+m}{m} x^m

    Here, (3n+2+mm)\binom{3n+2+m}{m} is the binomial coefficient.

  2. The first few terms of the expansion are:

    1(1x)3n+3=1+(3n+3)x+(3n+3)(3n+4)2!x2+(3n+3)(3n+4)(3n+5)3!x3+\frac{1}{(1 - x)^{3n+3}} = 1 + (3n+3) x + \frac{(3n+3)(3n+4)}{2!} x^2 + \frac{(3n+3)(3n+4)(3n+5)}{3!} x^3 + \cdots

Conclusion:

This gives the infinite series representation of 1(1x)3n+3\frac{1}{(1 - x)^{3n+3}}. Each term involves increasingly larger powers of xx and binomial coefficients based on 3n+33n + 3.

Would you like more details or clarifications?

5 Related Questions:

  1. How is the binomial expansion applied to negative exponents?
  2. Can you show the first four terms of the expansion for a specific value of nn?
  3. How does the convergence of this series depend on xx?
  4. What is the general term in a binomial expansion?
  5. How can this series expansion be applied in practical problems?

Tip:

For series expansions, always check the convergence radius to ensure the expansion is valid for the values of xx you're working with.

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Math Problem Analysis

Mathematical Concepts

Binomial Series
Power Series Expansion
Algebra

Formulas

Binomial series expansion: (1 - x)^{-k} = Σ (binom(k+m-1, m)) x^m

Theorems

Binomial Theorem

Suitable Grade Level

Grades 11-12, College Level