Proving the Binomial Theorem with Induction

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SUMMARY

The discussion focuses on proving the Binomial Theorem using mathematical induction. The theorem states that (x+y)^n equals the sum from k=0 to n of (x^k)*(y^(n-k)) multiplied by the binomial coefficient (n,k). The user initially demonstrates the base case for n=1 and seeks guidance on completing the induction step for n=n_0+1. A suggestion is provided to utilize Pascal's Triangle to facilitate the proof, emphasizing the relationship between the coefficients in the triangle and the binomial expansion.

PREREQUISITES
  • Understanding of mathematical induction
  • Familiarity with the Binomial Theorem
  • Knowledge of Pascal's Triangle
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the principles of mathematical induction in depth
  • Explore the properties and applications of Pascal's Triangle
  • Practice proving the Binomial Theorem using different methods
  • Learn about combinatorial interpretations of binomial coefficients
USEFUL FOR

Students of mathematics, educators teaching algebra and combinatorics, and anyone interested in understanding the foundations of the Binomial Theorem and its proofs.

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It seems like this shouldn't be too difficult and yet I'm stumped.
I am trying to prove the binomial theorem.

(x+y)^n = the sum from k=0 to n of (x^k)*(y^n-k)*(The binomial coefficient n,k)

Sorry, about the notation...

Anyway, I figure the best way to go about proving this is by induction.
It is easy to show that its true for n=1.
Then I assume that there exists an n_0 such that it is true for all n < n_0.
Now I want to show that the existence of this n_0 implies that the proposition is also true for n=n_0+1.

This is where I get stuck...
My question is, is this even the best way to go about proving this? If so, how can I finish the proof?

Maybe it would be better to give me a hint so I can figure it out on my own...
 
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http://planetmath.org/encyclopedia/InductiveProofOfBinomialTheorem.html

Go to the above link
 
Last edited by a moderator:
What you need to do is look at Pascal's Triangle. You should be aware of the simple procedure required for you to recreate the triangle yourself. You have to show that the number in one spot is equal to the sum of the two numbers above it. Now assume as your inductive hypothesis that the binomial expansion works for the exponent k. To prove that it works for exponent k+1, multiply the assumed expansion for k by just (a - b) (or whatever you are using for the base where the exponent is k), and use the facts just mentioned about Pascal's triangle to show that the expansion takes the desired form for k+1 as well.

EDIT: which is precisely what PlanetMath seems to tell you. :redface:
 
Last edited:

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