Page 1 COMP 170 L2 L03: Binomial Coefficients Purpose Properties of binomial coefficients Related issues: the Binomial Theorem and labeling
Dec 20, 2015
Page 1COMP 170 L2
L03: Binomial Coefficients
Purpose Properties of binomial coefficients
Related issues: the Binomial Theorem and
labeling
Page 2COMP 170 L2
Outline
Basic properties
Pascal’s triangle
The Binomial theorem
Labeling and Trinomial coefficients
Page 14COMP 170 L2
Outline
Basic properties
Pascal’s triangle
The Binomial theorem
Labeling and Trinomial coefficients
Page 19COMP 170 L2
Algebraic Proof of Pascal’s Relationship
For reference only. Will give proof by sum principle. More revealing.
Page 24COMP 170 L2
Outline
Basic properties
Pascal’s triangle
The Binomial theorem
Labeling and Trinomial coefficients
Page 27COMP 170 L2
Examples
Monomial terms: Lists of length two, each element can either be x or y.
How many monomial terms with one y (and hence one x) ?
= number of ways to choose 1 place among 2 places That is the coefficient for the term
Similarly Coefficient for
= number of lists having 0 place for y = Coefficient for
= number of lists having 2 places for y =
So
Page 28COMP 170 L2
Examples
Coefficient for = number of ways to choose 2 places for 3 places.
Coefficient for = number of ways to choose i places from 3 places
Page 29COMP 170 L2
Proof of the Binomial Theorem
Coefficient of = number of lists having y in k places
=number of ways to choose k places from n places
=
Page 32COMP 170 L2
Outline
Basic properties
Pascal’s triangle
The Binomial theorem
Labeling and Trinomial coefficients