Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
10. Combinatorics & Probability
Combinatorics
Problem 1
Textbook Question
In Exercises 1–8, evaluate the given binomial coefficient. 

1
Identify the binomial coefficient to evaluate: \( \binom{8}{3} \).
Recall the formula for a binomial coefficient: \( \binom{n}{k} = \frac{n!}{k!(n-k)!} \).
Substitute the values into the formula: \( \binom{8}{3} = \frac{8!}{3!(8-3)!} \).
Simplify the expression: \( \binom{8}{3} = \frac{8!}{3!5!} \).
Calculate the factorials and simplify the fraction: \( \frac{8 \times 7 \times 6 \times 5!}{3 \times 2 \times 1 \times 5!} \).

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Binomial Coefficient
A binomial coefficient, denoted as (n choose k) or C(n, k), represents the number of ways to choose k elements from a set of n elements without regard to the order of selection. It is calculated using the formula C(n, k) = n! / (k!(n-k)!), where '!' denotes factorial, the product of all positive integers up to that number.
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Factorial
The factorial of a non-negative integer n, denoted as n!, is the product of all positive integers from 1 to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120. Factorials are fundamental in combinatorics, particularly in calculating permutations and combinations, including binomial coefficients.
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Combinatorial Interpretation
The combinatorial interpretation of binomial coefficients provides a way to understand their significance in counting problems. For instance, (8 choose 3) can be interpreted as the number of ways to select 3 objects from a total of 8, which is crucial in probability, statistics, and various applications in mathematics.
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