/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 1.7 Give an analytic proof of Equati... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Give an analytic proof of Equation (4.1).

Short Answer

Expert verified

It is proved thatnr=nn-r.

Step by step solution

01

Step 1. Given information.

We have to prove the combinatorial explanation of the identity, that isnr=nn-r.

02

Step 2. Prove the combinatorial explanation of the identity.

The combinatorial explanation of the identity is nr=nn-r.

Taking L.H.S, we have nr.

Since role="math" localid="1647855220565" xr=x!r!(x-r)!, so

nr=n!r!(n-r)!

Therefore, L.H.S = role="math" localid="1647855382907" n!r!n-r!

Taking R.H.S, we have nn-r

Since xr=x!r!(x-r)!, so

nn-r=n!n-r!(n-n+r)!=n!r!(n-r)!

Therefore, R.H.S =n!r!n-r!

As L.H.S = R.H.S, hence it is proved thatnr=nn-r.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Expandx1+2x2+3x34.

The following identity is known as Fermat’s combinatorial identity:

nk=∑i=kni-1k-1n≥k

Give a combinatorial argument (no computations are needed) to establish this identity.

Hint: Consider the set of numbers 1 through n. How many subsets of size k have i as their highest numbered member?

From a group of npeople, suppose that we want to choose a committee of k, k≤n, one of whom is to be designated as chairperson.

(a) By focusing first on the choice of the committee and then on the choice of the chair, argue that there are role="math" localid="1647945358534" nkkpossible choices.

(b) By focusing first on the choice of the non-chair committee members and then on the choice of the chair, argue that there are role="math" localid="1647945372759" nk-1n-k+1possible choices.

(c) By focusing first on the choice of the chair and then on the choice of the other committee members, argue that

there are role="math" localid="1647945385288" nn-1k-1possible choices.

(d) Conclude from parts (a), (b), and (c) that role="math" localid="1647945400273" knk=n-k+1nk-1=nn-1k-1.

(e) Use the factorial definition ofmr to verify the identity in part (d).

Consider n-digit numbers where each digit is one of the 10integers 0,1,...,9. How many such numbers are there for which

(a) no two consecutive digits are equal?

(b) 0 appears as a digit a total of itimes, i=0,...,n?

In how many ways can 3novels, 2mathematics books, and 1chemistry book be arranged on a bookshelf if

(a) the books can be arranged in any order?

(b) the mathematics books must be together and the novels must be together?

(c) the novels must be together, but the other books can be arranged in any order?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.