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Ch. 8 - Sequences, Induction, and Probability
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
9장, 문제 4

Use the formula for nPr to evaluate each expression. 10P4

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Recall the formula for permutations: \(\displaystyle {}_nP_r = \frac{n!}{(n-r)!}\), where \(n\) is the total number of items and \(r\) is the number of items to arrange.
Identify the values of \(n\) and \(r\) from the problem: here, \(n = 10\) and \(r = 4\).
Substitute these values into the permutation formula: \(\displaystyle {}_{10}P_4 = \frac{10!}{(10-4)!} = \frac{10!}{6!}\).
Simplify the factorial expression by expanding \$10!\( only as far as needed to cancel with \)6!$: \(\displaystyle \frac{10 \times 9 \times 8 \times 7 \times 6!}{6!}\).
Cancel the \$6!$ terms and multiply the remaining numbers: \(10 \times 9 \times 8 \times 7\) to find the number of permutations.

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Permutation Formula

The permutation formula, denoted as nPr, calculates the number of ways to arrange r objects from a set of n distinct objects where order matters. It is given by nPr = n! / (n - r)!, where '!' denotes factorial.
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7:11
Introduction to Permutations

Factorial Function

A factorial, represented by n!, is the product of all positive integers from 1 up to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120. Factorials are essential in permutations and combinations to count arrangements.
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5:22
Factorials

Evaluating Permutations

To evaluate a permutation like 10P4, substitute into the formula: 10P4 = 10! / (10 - 4)! = 10! / 6!. Simplify by canceling common factorial terms and compute the product of the remaining factors.
추천 영상:
7:11
Introduction to Permutations