Chapter 9: Problem 43
For the following exercises, write the first four terms of the sequence. $$ a_{n}=\frac{n !}{n^{2}} $$
Short Answer
Expert verified
The first four terms are 1, \( \frac{1}{2} \), \( \frac{2}{3} \), \( \frac{3}{2} \).
Step by step solution
01
Evaluate the formula for n=1
Substitute 1 into the formula: \( a_{1} = \frac{1!}{1^2} = \frac{1}{1} = 1 \). Therefore, the first term is 1.
02
Evaluate the formula for n=2
Substitute 2 into the formula: \( a_{2} = \frac{2!}{2^2} = \frac{2 \times 1}{4} = \frac{2}{4} = \frac{1}{2} \). Therefore, the second term is \( \frac{1}{2} \).
03
Evaluate the formula for n=3
Substitute 3 into the formula: \( a_{3} = \frac{3!}{3^2} = \frac{3 \times 2 \times 1}{9} = \frac{6}{9} = \frac{2}{3} \). Therefore, the third term is \( \frac{2}{3} \).
04
Evaluate the formula for n=4
Substitute 4 into the formula: \( a_{4} = \frac{4!}{4^2} = \frac{4 \times 3 \times 2 \times 1}{16} = \frac{24}{16} = \frac{3}{2} \). Therefore, the fourth term is \( \frac{3}{2} \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Factorial
The concept of a factorial is exciting and unique in mathematics. It is denoted by an exclamation mark (!). The factorial of a non-negative integer, say \( n \), is the product of all positive integers less than or equal to \( n \). So, for instance:
- \( 0! = 1 \) by definition.
- \( 1! = 1 \)
- \( 2! = 2 \times 1 = 2 \)
- \( 3! = 3 \times 2 \times 1 = 6 \)
- \( 4! = 4 \times 3 \times 2 \times 1 = 24 \)
Algebraic Expressions
Algebraic expressions are mathematical phrases that can contain numbers, variables, and operation symbols. In your exercise, the algebraic expression is \( \frac{n!}{n^{2}} \). It combines factorials and exponents.
- The numerator, \( n! \), represents the factorial.
- The denominator, \( n^{2} \), represents the square of \( n \).
Step-by-Step Problem Solving
Solving math problems step-by-step is a powerful method to tackle seemingly complex problems. It allows you to break down a problem into manageable parts. In this exercise, each step represents evaluating the expression for different values of \( n \):
- Start with \( n = 1 \), evaluate the expression, and record the result.
- Repeat the process for \( n = 2, 3, \) and \( 4 \).
Evaluating Sequences
Evaluating sequences involves finding specific terms within a sequence as defined by a formula. In your exercise, the formula \( a_{n} = \frac{n!}{n^{2}} \) was given to write out the first four terms.
- By substituting \( n = 1 \), the first term \( a_1 \) was found as 1.
- For \( n = 2 \), the second term \( a_2 \) is \( \frac{1}{2} \).
- With \( n = 3 \), the third term \( a_3 \) is \( \frac{2}{3} \).
- Finally, substituting \( n = 4 \) yields the fourth term \( a_4 \) as \( \frac{3}{2} \).