Question

Evaluate each factorial. \(\frac{8 !}{3 ! 5 !}\)

Short answer

The simplified expression for \(\frac{8!}{3!5!}\) is 56.

Step-by-step solution

Expand the Factorial Terms

Write out the factorial for 8! and for the product of 3! and 5! to fully understand what numbers are being multiplied in each.

Cancel Out Common Terms

Cancel out the common terms that appear in both the numerator and the denominator. Since 5! is present in both the numerator and the denominator, and 3! is in the denominator, we have redundant multiplication that can be simplified.

Calculate the Remaining Values

After canceling out the common terms, multiply the remaining values in the numerator to get the final answer.

Key concepts

Factorials in Mathematics

The factorial of a non-negative integer, denoted by an exclamation mark (!), is the product of all positive integers less than or equal to that number. For example, the factorial of 5, or 5!, is calculated as 5 x 4 x 3 x 2 x 1, which equals 120. Factorials are used in various areas of mathematics, including permutations, combinations, and series expansions.

When working with factorial simplification, it's important to recognize patterns. For instance, in the expression \( \frac{8!}{3! 5!} \), we can see that 8! expands to 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1. Notice that 3! and 5! are factors within 8!, and therefore, this knowledge allows us to simplify the expression without having to multiply out the entire factorials. Remember that the factorial of zero, 0!, is always 1.

Numerical Problem Solving

Solving numerical problems, especially within the field of mathematics, involves a systematic approach to finding the solution using a series of understandable steps. In the case of our factorial problem, the first step is expanding the terms to see what they consist of, which provides a clearer picture of the problem we are dealing with. Once the terms are expanded, we can proceed to the next step.

Approaching numerical problems requires critical thinking to identify redundancies or patterns that can be utilized for simplification. It's not simply about doing the arithmetic; it's about observing and recognizing opportunities to simplify the calculation beforehand, which ultimately saves time and reduces the potential for errors.

Mathematical Simplification

Mathematical simplification aims to minimize the complexity of expressions while keeping the value unchanged. Returning to our sample problem \( \frac{8!}{3! 5!} \) and keeping the definition of factorials in mind, we can simplify by cancelling out the common terms in the numerator and the denominator. Specifically, 5! in the numerator and denominator cancel out, as do the terms in 3! (which are also in 8!). After the cancellation, we are left with a much simpler product of 8 x 7 x 6, leading to a straightforward calculation of 336.

Simplification can often be accomplished by recognizing and canceling shared factors, factoring expressions, combining like terms, or using algebraic properties. By practicing these strategies, students can improve their efficiency in solving a wide range of mathematical problems.