(x+y)^6 Binomial Expansion

4 min read Jun 17, 2024
(x+y)^6 Binomial Expansion

Binomial Expansion: Unveiling the Secrets of (x+y)^6

The binomial theorem is a powerful tool in mathematics that allows us to expand expressions of the form (x + y)^n, where n is a non-negative integer. In this article, we will delve into the specifics of expanding (x + y)^6.

The Binomial Theorem: A Fundamental Principle

The binomial theorem states:

(x + y)^n = ∑_(k=0)^n (n choose k) x^(n-k) y^k

where (n choose k) represents the binomial coefficient, calculated as n! / (k! * (n-k)!).

Unpacking (x + y)^6

Let's apply the binomial theorem to (x + y)^6:

(x + y)^6 = ∑_(k=0)^6 (6 choose k) x^(6-k) y^k

Now, we need to calculate the terms for each value of k:

  • k = 0: (6 choose 0) x^6 y^0 = x^6
  • k = 1: (6 choose 1) x^5 y^1 = 6x^5y
  • k = 2: (6 choose 2) x^4 y^2 = 15x^4y^2
  • k = 3: (6 choose 3) x^3 y^3 = 20x^3y^3
  • k = 4: (6 choose 4) x^2 y^4 = 15x^2y^4
  • k = 5: (6 choose 5) x^1 y^5 = 6xy^5
  • k = 6: (6 choose 6) x^0 y^6 = y^6

Therefore, the complete expansion of (x + y)^6 is:

(x + y)^6 = x^6 + 6x^5y + 15x^4y^2 + 20x^3y^3 + 15x^2y^4 + 6xy^5 + y^6

Key Observations

  • Symmetry: Notice that the coefficients are symmetrical, mirroring each other from the beginning and end of the expansion.
  • Pascal's Triangle: The coefficients (1, 6, 15, 20, 15, 6, 1) correspond to the 7th row of Pascal's Triangle.

Applications and Significance

The binomial expansion has widespread applications in various fields, including:

  • Algebra: Simplifying complex expressions.
  • Calculus: Deriving formulas for derivatives and integrals.
  • Probability: Calculating probabilities in binomial distributions.
  • Computer science: Designing algorithms for data analysis.

Conclusion

Understanding the binomial expansion, particularly for cases like (x + y)^6, provides a powerful tool for manipulating algebraic expressions and solving problems in diverse fields. This principle, grounded in the elegance of Pascal's Triangle, continues to be a fundamental concept in mathematics.

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