DOCSLIB.ORG

8.6 the BINOMIAL THEOREM We Remake Nature by the Act of Discovery, in the Poem Or in the Theorem

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

pg476 [V] G2 5-36058 / HCG / Cannon & Elich cr 11-30-95 MP1 476 Chapter 8 Discrete Mathematics: Functions on the Set of Natural Numbers (b) Based on your results for (a), guess the minimum number of handshakes. See Exercise 19, page 469. number of moves required if you start with an arbi- Show trary number of n disks. (Hint: Tohelpseeapat- n~n 2 1! tern,add1tothenumberofmovesforn51, 2, 3, f ~n! 5 for every positive integer n. 4.) 2 (c) A legend claims that monks in a remote monastery 56. Suppose n is an odd positive integer not divisible by 3. areworkingtomoveasetof64disks,andthatthe Show that n 2 2 1 is divisible by 24. (Hint: Consider the world will end when they complete their sacred three consecutive integers n 2 1, n, n 1 1. Explain task. Moving one disk per second without error, 24 why the product ~n 2 1!~n 1 1! must be divisible by 3 hours a day, 365 days a year, how long would it take andby8.) to move all 64 disks? 57. Finding Patterns If an 5 Ï24n 1 1, (a) write out 55. Number of Handshakes Suppose there are n people the first five terms of the sequence $an%. (b) What odd at a party and that each person shakes hands with every integers occur in $an%? (c) Explain why $an% contains all other person exactly once. Let f~n! denote the total primes greater than 3. (Hint: UseExercise56.) 8.6 THE BINOMIAL THEOREM We remake nature by the act of discovery, in the poem or in the theorem. And the great poem and the great theorem are new to every reader, and yet are his own experiences, because he himself recreates them. @And# in the instant when the mind seizes this for itself, in art or in science, the heart misses a beat. J. Bronowski In this section we derive a general formula to calculate an expansion for ~a 1 b!n for any positive integer power n,ortofindanyparticularterminsuchanexpansion. We begin by calculating the first few powers directly and then look for significant patterns. To go from one power of ~a 1 b! to the next, we simply multiply by ~a 1 b!: ~a 1 b!1 5 a 1 b ~a 1 b!2 5 a2 1 2ab 1 b 2 ~a 1 b!3 5 a3 1 3a2b 1 3ab 2 1 b 3 ~3! a 1 b a4 1 3a3b 1 3a2b 2 1 ab 3 3 2 2 3 4 The thing that started it a b 1 3a b 1 3ab 1 b Add like terms all was this silly newspaper puzzle that asked you to count up the total number ~a 1 b!4 5 a 4 1 4a 3b 1 6a 2b 2 1 4ab 3 1 b 4 of ways you could spell the words “Pyramid of Values” ~3! a 1 b from a triangular array of letters. This led my friend a5 1 4a4b 1 6a3b 2 1 4a 2b 3 1 ab 4 and me to discover Pascal’s a4b 1 4a3b 2 1 6a2b 3 1 4ab 4 1 b 5 Add like terms triangle. This happened in grade 10 or 11. Bill Gosper ~a 1 b!5 5 a 5 1 5a 4b 1 10a3b 2 1 10a2b 3 1 5ab 4 1 b 5 pg477 [R] G1 5-36058 / HCG / Cannon & Elich kr 11-20-95 QC1 8.6 The Binomial Theorem 477 When we look at these expansions of ~a 1 b!n for n 5 1, 2, 3, 4, and 5, several patterns become apparent. 1. There are n 1 1 terms, from an to b n. 2. Every term has essentially the same form: some coefficient times the product of a power of a times a power of b. 3. In each term the sum of the exponents on a and b is always n. 4. The powers (exponents) on a decrease, term by term, from n down to 0 where the last term is given by b n 5 a0b n, and the exponents on b in- crease from 0 to n. Knowing the form of the terms in the expansion and that the sum of the powers is always n, we will have the entire expansion when we know how to calculate the coefficients of the terms. If we display the coefficients from the computations above, we find precisely the numbers in the first few rows of Pascal’s triangle: 11 121 1331 14641 15101051 Using the address notation for Pascal’s triangle that we introduced in Section 5 5 5 5 5 5 8.4, the last row of coefficients in the triangle is ~ 0!, ~ 1 !, ~ 2!, ~ 3!, ~ 4!, ~ 5!,andso we may write the expansion for ~a 1 b!5: 5 5 5 5 ~a 1 b!5 5 a5b 0 1 a4b 1 1 a3b 2 1 a2b 3 S0D S1D S2D S3D 5 5 1 a1b 4 1 a0b 5 S4D S5D 5 Each term exhibits the same form. For n 5 5, each coefficient has the form ~r!, where r is also the exponent on b. For each term the sum of the exponents on a and b is always 5, so that when we have b r, we must also have a 52r.Finally,sincethe first term has r 5 0, the second term has r 5 1, etc., the ~r 1 1!st term involves r. This leads to a general conjecture for the expansion of ~a 1 b!n which we state as a theorem that can be proved using mathematical induction. (See the end of this section.) Binomial theorem Suppose n is any positive integer. The expansion of ~a 1 b!n is given by n n n n ~a 1 b!n 5 a nb 0 1 a n21b 1 1 ···1 an2rbr 1···1 a0bn S0D S1D SrD SnD (1) n where the ~r 1 1!st term is a n2rb r,0#r#n. In summation notation, Sr D n n ~a 1 b!n 5 an2rb r. (2) ro50 SrD pg478 [V] G2 5-36058 / HCG / Cannon & Elich kr 11-20-95 QC1 478 Chapter 8 Discrete Mathematics: Functions on the Set of Natural Numbers At this point, we have established only that the form of our conjecture is valid for the first five values of n, and we have not completely justified our use of the name Pascal’s triangle of binomial coefficients. Nonetheless, the multiplication of ~a 1 b!4 by ~a 1 b! to get the expansion for ~a 1 b!5 contains all the essential ideas of the proof. We still lack a closed-form formula for the binomial coefficients. We know, for 20 20 17 3 example, that the fourth term of the expansion of ~x 1 2y! is ~ 3 !x ~2y! ,butwe 20 cannot complete the calculation without the binomial coefficient ~ 3 !.Thiswould require writing at least the first few terms of 20 rows of Pascal’s triangle. Pascal himself posed and solved the problem of computing the entry at any n given address within the triangle. He observed that to find ~r!,wecantakethe product of all the numbers from 1 through r,anddivideitintotheproductofthe same number of integers, from n downward. This leads to the following formula. Pascal’s formula for binomial coefficients Suppose n is a positive integer and r is an integer that satisfies 0 , r # n. n The binomial coefficient is given by S rD n n~n 2 1! ···~n2r11! 5 (3) SrD 1·2·3···r We leave it to the reader to verify that the last factor in the numerator, ~n 2 r 1 1!,istherth number counting down from n. This gives the same number of factors in the numerator as in the denominator. cEXAMPLE 1 Using Pascal’s formula Find the first five binomial coefficients on the tenth row of Pascal’s triangle, and then give the first five terms of the expansion of ~a 1 b!10. Solution 10 Strategy: We know ~ 0 ! 5 Follow the strategy. 1. Use Equation (3) to get 10 10 10 10·9 10 10·9·8 the remaining coefficients. 5 5 10, 5 545, 5 5120, and S 1 D 1 S 2 D 1·2 S 3 D 1·2·3 10 10·9·8·7 5 5210. S 4 D 1·2·3·4 Therefore the first five terms in the expansions of ~a 1 b!10 are a10 1 10a9b 1 45a8b 2 1 120a7b 3 1 210a6b 4. b There is another very common formula for binomial coefficients that uses factori- als. Equation (3) has a factorial in the denominator, and we can get a factorial in the numerator if we multiply numerator and denominator by the product of the rest of the integers from n 2 r downto1: n n~n21!...~n2r11! 5 SrD 1·2·...r n~n21!...~n2r11! ~n2r!...2·1 n! 5 · 5 . r! ~n2r!...2·1 r!~n2r!! pg479 [R] G5 5-36058 / HCG / Cannon & Elich kr 12-4-95 OT1 8.6 The Binomial Theorem 479 HISTORICAL NOTE BLAISE PASCAL Pascal’s triangle is named after At the age of 29, Pascal had a Blaise Pascal, born in France in conversion experience that led to a 1623. Pascal was an individual of vow to renounced mathematics for incredible talent and breadth who a life of religious contemplation. made basic contributions in many Before that time, however, in areas of mathematics, but who died addition to his foundational work in early after spending much of life geometry, he built a mechanical embroiled in bitter philosophical computing machine (in honor of and religious wrangling.
Recommended publications
  • An Appreciation of Euler's Formula

    An Appreciation of Euler's Formula

    Rose-Hulman Undergraduate Mathematics Journal Volume 18 Issue 1 Article 17 An Appreciation of Euler's Formula Caleb Larson North Dakota State University Follow this and additional works at: https://scholar.rose-hulman.edu/rhumj Recommended Citation Larson, Caleb (2017) "An Appreciation of Euler's Formula," Rose-Hulman Undergraduate Mathematics Journal: Vol. 18 : Iss. 1 , Article 17. Available at: https://scholar.rose-hulman.edu/rhumj/vol18/iss1/17 Rose- Hulman Undergraduate Mathematics Journal an appreciation of euler's formula Caleb Larson a Volume 18, No. 1, Spring 2017 Sponsored by Rose-Hulman Institute of Technology Department of Mathematics Terre Haute, IN 47803 [email protected] a scholar.rose-hulman.edu/rhumj North Dakota State University Rose-Hulman Undergraduate Mathematics Journal Volume 18, No. 1, Spring 2017 an appreciation of euler's formula Caleb Larson Abstract. For many mathematicians, a certain characteristic about an area of mathematics will lure him/her to study that area further. That characteristic might be an interesting conclusion, an intricate implication, or an appreciation of the impact that the area has upon mathematics. The particular area that we will be exploring is Euler's Formula, eix = cos x + i sin x, and as a result, Euler's Identity, eiπ + 1 = 0. Throughout this paper, we will develop an appreciation for Euler's Formula as it combines the seemingly unrelated exponential functions, imaginary numbers, and trigonometric functions into a single formula. To appreciate and further understand Euler's Formula, we will give attention to the individual aspects of the formula, and develop the necessary tools to prove it.
  • Newton and Leibniz: the Development of Calculus Isaac Newton (1642-1727)

    Newton and Leibniz: the Development of Calculus Isaac Newton (1642-1727)

    Newton and Leibniz: The development of calculus Isaac Newton (1642-1727) Isaac Newton was born on Christmas day in 1642, the same year that Galileo died. This coincidence seemed to be symbolic and in many ways, Newton developed both mathematics and physics from where Galileo had left off. A few months before his birth, his father died and his mother had remarried and Isaac was raised by his grandmother. His uncle recognized Newton’s mathematical abilities and suggested he enroll in Trinity College in Cambridge. Newton at Trinity College At Trinity, Newton keenly studied Euclid, Descartes, Kepler, Galileo, Viete and Wallis. He wrote later to Robert Hooke, “If I have seen farther, it is because I have stood on the shoulders of giants.” Shortly after he received his Bachelor’s degree in 1665, Cambridge University was closed due to the bubonic plague and so he went to his grandmother’s house where he dived deep into his mathematics and physics without interruption. During this time, he made four major discoveries: (a) the binomial theorem; (b) calculus ; (c) the law of universal gravitation and (d) the nature of light. The binomial theorem, as we discussed, was of course known to the Chinese, the Indians, and was re-discovered by Blaise Pascal. But Newton’s innovation is to discuss it for fractional powers. The binomial theorem Newton’s notation in many places is a bit clumsy and he would write his version of the binomial theorem as: In modern notation, the left hand side is (P+PQ)m/n and the first term on the right hand side is Pm/n and the other terms are: The binomial theorem as a Taylor series What we see here is the Taylor series expansion of the function (1+Q)m/n.
  • Mathematics (MATH)

    Mathematics (MATH)

    Course Descriptions MATH 1080 QL MATH 1210 QL Mathematics (MATH) Precalculus Calculus I 5 5 MATH 100R * Prerequisite(s): Within the past two years, * Prerequisite(s): One of the following within Math Leap one of the following: MAT 1000 or MAT 1010 the past two years: (MATH 1050 or MATH 1 with a grade of B or better or an appropriate 1055) and MATH 1060, each with a grade of Is part of UVU’s math placement process; for math placement score. C or higher; OR MATH 1080 with a grade of C students who desire to review math topics Is an accelerated version of MATH 1050 or higher; OR appropriate placement by math in order to improve placement level before and MATH 1060. Includes functions and placement test. beginning a math course. Addresses unique their graphs including polynomial, rational, Covers limits, continuity, differentiation, strengths and weaknesses of students, by exponential, logarithmic, trigonometric, and applications of differentiation, integration, providing group problem solving activities along inverse trigonometric functions. Covers and applications of integration, including with an individual assessment and study inequalities, systems of linear and derivatives and integrals of polynomial plan for mastering target material. Requires nonlinear equations, matrices, determinants, functions, rational functions, exponential mandatory class attendance and a minimum arithmetic and geometric sequences, the functions, logarithmic functions, trigonometric number of hours per week logged into a Binomial Theorem, the unit circle, right functions, inverse trigonometric functions, and preparation module, with progress monitored triangle trigonometry, trigonometric equations, hyperbolic functions. Is a prerequisite for by a mentor. May be repeated for a maximum trigonometric identities, the Law of Sines, the calculus-based sciences.
  • The Discovery of the Series Formula for Π by Leibniz, Gregory and Nilakantha Author(S): Ranjan Roy Source: Mathematics Magazine, Vol

    The Discovery of the Series Formula for Π by Leibniz, Gregory and Nilakantha Author(S): Ranjan Roy Source: Mathematics Magazine, Vol

    The Discovery of the Series Formula for π by Leibniz, Gregory and Nilakantha Author(s): Ranjan Roy Source: Mathematics Magazine, Vol. 63, No. 5 (Dec., 1990), pp. 291-306 Published by: Mathematical Association of America Stable URL: http://www.jstor.org/stable/2690896 Accessed: 27-02-2017 22:02 UTC JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://about.jstor.org/terms Mathematical Association of America is collaborating with JSTOR to digitize, preserve and extend access to Mathematics Magazine This content downloaded from 195.251.161.31 on Mon, 27 Feb 2017 22:02:42 UTC All use subject to http://about.jstor.org/terms ARTICLES The Discovery of the Series Formula for 7r by Leibniz, Gregory and Nilakantha RANJAN ROY Beloit College Beloit, WI 53511 1. Introduction The formula for -r mentioned in the title of this article is 4 3 57 . (1) One simple and well-known moderm proof goes as follows: x I arctan x = | 1 +2 dt x3 +5 - +2n + 1 x t2n+2 + -w3 - +(-I)rl2n+1 +(-I)l?lf dt. The last integral tends to zero if Ix < 1, for 'o t+2dt < jt dt - iX2n+3 20 as n oo.
  • 1. More Examples Example 1. Find the Slope of the Tangent Line at (3,9)

    1. More Examples Example 1. Find the Slope of the Tangent Line at (3,9)

    1. More examples Example 1. Find the slope of the tangent line at (3; 9) to the curve y = x2. P = (3; 9). So Q = (3 + ∆x; 9 + ∆y). 9 + ∆y = (3 + ∆x)2 = (9 + 6∆x + (∆x)2. Thus, we have ∆y = 6 + ∆x. ∆x If we let ∆ go to zero, we get ∆y lim = 6 + 0 = 6. ∆x→0 ∆x Thus, the slope of the tangent line at (3; 9) is 6. Let's consider a more abstract example. Example 2. Find the slope of the tangent line at an arbitrary point P = (x; y) on the curve y = x2. Again, P = (x; y), and Q = (x + ∆x; y + ∆y), where y + ∆y = (x + ∆x)2 = x2 + 2x∆x + (∆x)2. So we get, ∆y = 2x + ∆x. ∆x Letting ∆x go to zero, we get ∆y lim = 2x + 0 = 2x. ∆x→0 ∆x Thus, the slope of the tangent line at an arbitrary point (x; y) is 2x. Example 3. Find the slope of the tangent line at an arbitrary point P = (x; y) on the curve y = ax3, where a is a real number. Q = (x + ∆x; y + ∆y). We get, 1 2 y + ∆y = a(x + ∆x)3 = a(x3 + 3x2∆x + 3x(∆x)2 + (∆x)3). After simplifying we have, ∆y = 3ax2 + 3xa∆x + a(∆x)2. ∆x Letting ∆x go to 0 we conclude, ∆y 2 2 mP = lim = 3ax + 0 + 0 = 3ax . x→0 ∆x 2 Thus, the slope of the tangent line at a point (x; y) is mP = 3ax . Example 4.
  • Multipermutations 1.1. Generating Functions

    Multipermutations 1.1. Generating Functions

    CORE Metadata, citation and similar papers at core.ac.uk Provided by Elsevier - Publisher Connector JOURNALOF COMBINATORIALTHEORY, Series A 67, 44-71 (1994) The r- Multipermutations SEUNGKYUNG PARK Department of Mathematics, Yonsei University, Seoul 120-749, Korea Communicated by Gian-Carlo Rota Received October 1, 1992 In this paper we study permutations of the multiset {lr, 2r,...,nr}, which generalizes Gesse| and Stanley's work (J. Combin. Theory Ser. A 24 (1978), 24-33) on certain permutations on the multiset {12, 22..... n2}. Various formulas counting the permutations by inversions, descents, left-right minima, and major index are derived. © 1994 AcademicPress, Inc. 1. THE r-MULTIPERMUTATIONS 1.1. Generating Functions A multiset is defined as an ordered pair (S, f) where S is a set and f is a function from S to the set of nonnegative integers. If S = {ml ..... mr}, we write {m f(mD, .... m f(mr)r } for (S, f). Intuitively, a multiset is a set with possibly repeated elements. Let us begin by considering permutations of multisets (S, f), which are words in which each letter belongs to the set S and for each m e S the total number of appearances of m in the word is f(m). Thus 1223231 is a permutation of the multiset {12, 2 3, 32}. In this paper we consider a special set of permutations of the multiset [n](r) = {1 r, ..., nr}, which is defined as follows. DEFINITION 1.1. An r-multipermutation of the set {ml ..... ran} is a permutation al ""am of the multiset {m~ ....
  • 40 Chapter 6 the BINOMIAL THEOREM in Chapter 1 We Defined

    40 Chapter 6 the BINOMIAL THEOREM in Chapter 1 We Defined

    Chapter 6 THE BINOMIAL THEOREM n In Chapter 1 we defined as the coefficient of an-rbr in the expansion of (a + b)n, and r tabulated these coefficients in the arrangement of the Pascal Triangle: n Coefficients of (a + b)n 0 1 1 1 1 2 1 2 1 3 1 3 3 1 4 1 4 6 4 1 5 1 5 10 10 5 1 6 1 6 15 20 15 6 1 ... n n We then observed that this array is bordered with 1's; that is, ' 1 and ' 1 for n = 0 n 0, 1, 2, ... We also noted that each number inside the border of 1's is the sum of the two closest numbers on the previous line. This property may be expressed in the form n n n%1 (1) % ' . r&1 r r This formula provides an efficient method of generating successive lines of the Pascal Triangle, but the method is not the best one if we want only the value of a single binomial coefficient for a 100 large n, such as . We therefore seek a more direct approach. 3 It is clear that the binomial coefficients in a diagonal adjacent to a diagonal of 1's are the 40 n numbers 1, 2, 3, ... ; that is, ' n. Now let us consider the ratios of binomial coefficients 1 to the previous ones on the same row. For n = 4, these ratios are: (2) 4/1, 6/4 = 3/2, 4/6 = 2/3, 1/4. For n = 5, they are (3) 5/1, 10/5 = 2, 10/10 = 1, 5/10 = 1/2, 1/5.
  • Q-Combinatorics

    Q-Combinatorics

    q-combinatorics February 7, 2019 1 q-binomial coefficients n n Definition. For natural numbers n; k,the q-binomial coefficient k q (or just k if there no ambi- guity on q) is defined as the following rational function of the variable q: (qn − 1)(qn−1 − 1) ··· (q − 1) : (1.1) (qk − 1)(qk−1 − 1) ··· (q − 1) · (qn−k − 1)(qn−k−1 − 1) ··· (q − 1) For n = 0, k = 0, or n = k, we interpret the corresponding products 1, as the value of the empty product. If we exclude certain roots of unity from the domain of q, (1.1) is equal to (qn − 1)(qn−1 − 1) ··· (qn−k+1 − 1) (1.2) (qk − 1)(qk−1 − 1) ··· (q − 1) · 1 (qn−1 + ::: + q + 1) ··· (q2 + q + 1)(q + 1) · 1 = : (qk−1 + ::: + q + 1) ··· (q2 + q + 1)(q + 1) · 1(qn−k−1 + ::: + q + 1) ··· (q2 + q + 1)(q + 1) · 1 As the notation starts to be overwhelming, we introduce to q-analogue of the positive integer n, n−1 denoted by [n] or [n]q, as q + ::: + q + 1; and the q-analogue of the factorial of the positive integer n, denoted by [n]! or [n]q!, as [n]q! = [1]q · [2]q ··· [n]q. With this additional notation, we also can say n [n] ! = q ; (1.3) k q [k]q![n − k]q! when we avoid certain roots of unity with q. It is easy too see from (1.1) that n n = = 1 0 q n q and that for every 0 ≤ k ≤ n the symmetry rule n n = k q n − k q holds.
  • Leonhard Euler: His Life, the Man, and His Works∗

    Leonhard Euler: His Life, the Man, and His Works∗

    SIAM REVIEW c 2008 Walter Gautschi Vol. 50, No. 1, pp. 3–33 Leonhard Euler: His Life, the Man, and His Works∗ Walter Gautschi† Abstract. On the occasion of the 300th anniversary (on April 15, 2007) of Euler’s birth, an attempt is made to bring Euler’s genius to the attention of a broad segment of the educated public. The three stations of his life—Basel, St. Petersburg, andBerlin—are sketchedandthe principal works identified in more or less chronological order. To convey a flavor of his work andits impact on modernscience, a few of Euler’s memorable contributions are selected anddiscussedinmore detail. Remarks on Euler’s personality, intellect, andcraftsmanship roundout the presentation. Key words. LeonhardEuler, sketch of Euler’s life, works, andpersonality AMS subject classification. 01A50 DOI. 10.1137/070702710 Seh ich die Werke der Meister an, So sehe ich, was sie getan; Betracht ich meine Siebensachen, Seh ich, was ich h¨att sollen machen. –Goethe, Weimar 1814/1815 1. Introduction. It is a virtually impossible task to do justice, in a short span of time and space, to the great genius of Leonhard Euler. All we can do, in this lecture, is to bring across some glimpses of Euler’s incredibly voluminous and diverse work, which today fills 74 massive volumes of the Opera omnia (with two more to come). Nine additional volumes of correspondence are planned and have already appeared in part, and about seven volumes of notebooks and diaries still await editing! We begin in section 2 with a brief outline of Euler’s life, going through the three stations of his life: Basel, St.
  • The Binomial Theorem and Combinatorial Proofs Shagnik Das

    The Binomial Theorem and Combinatorial Proofs Shagnik Das

    The Binomial Theorem and Combinatorial Proofs Shagnik Das Introduction As we live our lives, we are faced with innumerable decisions on a daily basis1. Can I get away with wearing these clothes again before I have to wash them? Which frozen pizza should I have for dinner tonight? What excuse should I use for skipping the gym today? While it may at times seem tiring to be faced with all these choices on a regular basis, it is this exercise of free will that separates us from the machines we live with.2 This multitude of choices, then, provides some measure of our own vitality | the more options we have, the more alive we truly are. What, then, could be more important than being able to count how many options one actually has?4 As we have already seen during our first week of lectures, one of the main protagonists in these counting problems is the binomial coefficient, whose definition is given below. n Definition 1. Given non-negative integers n and k, the binomial coefficient k denotes the number of subsets of size k of a set of n elements. Equivalently, it is the number of unordered choices of k distinct elements from a set of n elements. However, the binomial coefficient leads a double life. Not only does it have the above definition, but also the formula below, which we proved in lecture. Proposition 2. For non-negative integers n and k, n nk n(n − 1)(n − 2) ::: (n − k + 1) n! = = = : k k! k! k!(n − k)! In this note, we will prove several more facts about this most fascinating of creatures.
  • Chapter 3.3, 4.1, 4.3. Binomial Coefficient Identities

    Chapter 3.3, 4.1, 4.3. Binomial Coefficient Identities

    Chapter 3.3, 4.1, 4.3. Binomial Coefficient Identities Prof. Tesler Math 184A Winter 2019 Prof. Tesler Binomial Coefficient Identities Math 184A / Winter 2019 1 / 36 Table of binomial coefficients n k k = 0 k = 1 k = 2 k = 3 k = 4 k = 5 k = 6 n = 0 1 0 0 0 0 0 0 n = 1 1 1 0 0 0 0 0 n = 2 1 2 1 0 0 0 0 n = 3 1 3 3 1 0 0 0 n = 4 1 4 6 4 1 0 0 n = 5 1 5 10 10 5 1 0 n = 6 1 6 15 20 15 6 1 n n! Compute a table of binomial coefficients using = . k k! (n - k)! We’ll look at several patterns. First, the nonzero entries of each row are symmetric; e.g., row n = 4 is 4 4 4 4 4 0 , 1 , 2 , 3 , 4 = 1, 4, 6, 4, 1 , n n which reads the same in reverse. Conjecture: k = n-k . Prof. Tesler Binomial Coefficient Identities Math 184A / Winter 2019 2 / 36 A binomial coefficient identity Theorem For nonegative integers k 6 n, n n n n = including = = 1 k n - k 0 n First proof: Expand using factorials: n n! n n! = = k k! (n - k)! n - k (n - k)! k! These are equal. Prof. Tesler Binomial Coefficient Identities Math 184A / Winter 2019 3 / 36 Theorem For nonegative integers k 6 n, n n n n = including = = 1 k n - k 0 n Second proof: A bijective proof. We’ll give a bijection between two sets, one counted by the left n n side, k , and the other by the right side, n-k .
  • The Legacy of Leonhard Euler: a Tricentennial Tribute (419 Pages)

    The Legacy of Leonhard Euler: a Tricentennial Tribute (419 Pages)

    P698.TP.indd 1 9/8/09 5:23:37 PM This page intentionally left blank Lokenath Debnath The University of Texas-Pan American, USA Imperial College Press ICP P698.TP.indd 2 9/8/09 5:23:39 PM Published by Imperial College Press 57 Shelton Street Covent Garden London WC2H 9HE Distributed by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. THE LEGACY OF LEONHARD EULER A Tricentennial Tribute Copyright © 2010 by Imperial College Press All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN-13 978-1-84816-525-0 ISBN-10 1-84816-525-0 Printed in Singapore. LaiFun - The Legacy of Leonhard.pmd 1 9/4/2009, 3:04 PM September 4, 2009 14:33 World Scientific Book - 9in x 6in LegacyLeonhard Leonhard Euler (1707–1783) ii September 4, 2009 14:33 World Scientific Book - 9in x 6in LegacyLeonhard To my wife Sadhana, grandson Kirin,and granddaughter Princess Maya, with love and affection.