Math Problem Statement

(x^ 2 -1)^ n = x ^ (2n) - n * x ^ (2n - 2) +***

Solution

The expression you provided appears to be the beginning of a binomial expansion. Let's expand the expression (x21)n(x^2 - 1)^n using the binomial theorem.

Binomial Theorem

The binomial theorem states that:

(a+b)n=k=0n(nk)ankbk(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k

In your case, a=x2a = x^2 and b=1b = -1. Applying the binomial theorem:

(x21)n=k=0n(nk)(x2)nk(1)k(x^2 - 1)^n = \sum_{k=0}^{n} \binom{n}{k} (x^2)^{n-k} (-1)^k

This expands to:

(x21)n=k=0n(nk)x2(nk)(1)k(x^2 - 1)^n = \sum_{k=0}^{n} \binom{n}{k} x^{2(n-k)} (-1)^k

Explicit Expansion

Let's expand the first few terms:

(x21)n=(n0)x2n(1)0+(n1)x2(n1)(1)1+(n2)x2(n2)(1)2+(x^2 - 1)^n = \binom{n}{0} x^{2n} (-1)^0 + \binom{n}{1} x^{2(n-1)} (-1)^1 + \binom{n}{2} x^{2(n-2)} (-1)^2 + \cdots

Simplifying:

(x21)n=x2n(n1)x2(n1)+(n2)x2(n2)(x^2 - 1)^n = x^{2n} - \binom{n}{1} x^{2(n-1)} + \binom{n}{2} x^{2(n-2)} - \cdots

This shows the general form of the expansion. The exact number of terms and their coefficients will depend on the value of nn.

Would you like a more detailed breakdown of the terms for a specific value of nn, or do you have any further questions?

Related Questions:

  1. How does the binomial theorem apply when expanding (1+x)n(1 + x)^n instead of (x21)n(x^2 - 1)^n?
  2. What happens when nn is a non-integer in the binomial expansion?
  3. Can you derive the general formula for the coefficient of x2(nk)x^{2(n-k)} in the expansion of (x21)n(x^2 - 1)^n?
  4. How does the expansion of (x21)n(x^2 - 1)^n change if we replace x2x^2 with another function, like x3x^3?
  5. What are some applications of binomial expansions in calculus or other areas of mathematics?

Tip:

When expanding binomials, it's helpful to write out the first few terms explicitly to identify patterns in coefficients and powers. This is especially useful when analyzing specific cases or simplifying complex expressions.

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Math Problem Analysis

Mathematical Concepts

Binomial Theorem
Binomial Expansion

Formulas

Binomial theorem

Theorems

Binomial theorem

Suitable Grade Level

Advanced High School