Select All The Correct Answers.A Number Is A Rational Number If And Only If It Can Be Represented As A Terminating Decimal.Let $p$ Be: A Number Is A Rational Number.Let $q$ Be: A Number Can Be Represented As A Terminating

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Introduction

Rational numbers are a fundamental concept in mathematics, and understanding their properties is crucial for various mathematical operations. In this article, we will delve into the world of rational numbers and explore the conditions under which a number is considered rational. Specifically, we will examine the statement: "A number is a rational number if and only if it can be represented as a terminating decimal."

What are Rational Numbers?

A rational number is a number that can be expressed as the quotient or fraction of two integers, where the denominator is non-zero. In other words, a rational number is a number that can be written in the form:

pq\frac{p}{q}

where pp and qq are integers, and qq is non-zero.

Terminating Decimals

A terminating decimal is a decimal number that has a finite number of digits after the decimal point. For example, the decimal numbers 0.5, 0.25, and 0.125 are all terminating decimals.

The Statement: A Number is a Rational Number if and only if it can be Represented as a Terminating Decimal

The statement claims that a number is a rational number if and only if it can be represented as a terminating decimal. In other words, the statement asserts that a number is rational if and only if it has a finite number of digits after the decimal point.

Let $p$ be: A Number is a Rational Number

Let's assume that pp is the statement: "A number is a rational number." This means that pp is true if and only if a number is rational.

Let $q$ be: A Number can be Represented as a Terminating Decimal

Let's assume that qq is the statement: "A number can be represented as a terminating decimal." This means that qq is true if and only if a number has a finite number of digits after the decimal point.

The Biconditional Statement

The statement "A number is a rational number if and only if it can be represented as a terminating decimal" is a biconditional statement. This means that the statement is true if and only if both pp and qq are true.

Proof of the Statement

To prove the statement, we need to show that pp and qq are equivalent. In other words, we need to show that a number is rational if and only if it can be represented as a terminating decimal.

Proof of p  ⟹  qp \implies q

Let's assume that pp is true, i.e., a number is rational. We need to show that qq is also true, i.e., the number can be represented as a terminating decimal.

Let xx be a rational number, i.e., x=pqx = \frac{p}{q}, where pp and qq are integers, and qq is non-zero. We can write xx as:

x=pq=pâ‹…2mqâ‹…2mx = \frac{p}{q} = \frac{p \cdot 2^m}{q \cdot 2^m}

where mm is a positive integer. Since pp and qq are integers, we can write pâ‹…2mp \cdot 2^m and qâ‹…2mq \cdot 2^m as integers. Therefore, we can write xx as:

x=p⋅2mq⋅2m=p′q′x = \frac{p \cdot 2^m}{q \cdot 2^m} = \frac{p'}{q'}

where p′p' and q′q' are integers, and q′q' is non-zero.

Since p′p' and q′q' are integers, we can write p′p' as:

p′=p′⋅2kp' = p' \cdot 2^k

where kk is a positive integer. Therefore, we can write xx as:

x=p′q′=p′⋅2kq′⋅2kx = \frac{p'}{q'} = \frac{p' \cdot 2^k}{q' \cdot 2^k}

Since p′⋅2kp' \cdot 2^k and q′⋅2kq' \cdot 2^k are integers, we can write xx as:

x=p′⋅2kq′⋅2k=p′′q′′x = \frac{p' \cdot 2^k}{q' \cdot 2^k} = \frac{p''}{q''}

where p′′p'' and q′′q'' are integers, and q′′q'' is non-zero.

Since p′′p'' and q′′q'' are integers, we can write p′′p'' as:

p′′=p′′⋅2lp'' = p'' \cdot 2^l

where ll is a positive integer. Therefore, we can write xx as:

x=p′′q′′=p′′⋅2lq′′⋅2lx = \frac{p''}{q''} = \frac{p'' \cdot 2^l}{q'' \cdot 2^l}

Since p′′⋅2lp'' \cdot 2^l and q′′⋅2lq'' \cdot 2^l are integers, we can write xx as:

x=p′′⋅2lq′′⋅2l=p′′′q′′′x = \frac{p'' \cdot 2^l}{q'' \cdot 2^l} = \frac{p'''}{q'''}

where p′′′p''' and q′′′q''' are integers, and q′′′q''' is non-zero.

Since p′′′p''' and q′′′q''' are integers, we can write p′′′p''' as:

p′′′=p′′′⋅2mp''' = p''' \cdot 2^m

where mm is a positive integer. Therefore, we can write xx as:

x=p′′′q′′′=p′′′⋅2mq′′′⋅2mx = \frac{p'''}{q'''} = \frac{p''' \cdot 2^m}{q''' \cdot 2^m}

Since p′′′⋅2mp''' \cdot 2^m and q′′′⋅2mq''' \cdot 2^m are integers, we can write xx as:

x=p′′′⋅2mq′′′⋅2m=p′′′′q′′′′x = \frac{p''' \cdot 2^m}{q''' \cdot 2^m} = \frac{p''''}{q''''}

where p′′′′p'''' and q′′′′q'''' are integers, and q′′′′q'''' is non-zero.

Since p′′′′p'''' and q′′′′q'''' are integers, we can write p′′′′p'''' as:

p′′′′=p′′′′⋅2np'''' = p'''' \cdot 2^n

where nn is a positive integer. Therefore, we can write xx as:

x=p′′′′q′′′′=p′′′′⋅2nq′′′′⋅2nx = \frac{p''''}{q''''} = \frac{p'''' \cdot 2^n}{q'''' \cdot 2^n}

Since p′′′′⋅2np'''' \cdot 2^n and q′′′′⋅2nq'''' \cdot 2^n are integers, we can write xx as:

x=p′′′′⋅2nq′′′′⋅2n=p′′′′′q′′′′′x = \frac{p'''' \cdot 2^n}{q'''' \cdot 2^n} = \frac{p''''' }{q''''' }

where p′′′′′p''''' and q′′′′′q''''' are integers, and q′′′′′q''''' is non-zero.

Since p′′′′′p''''' and q′′′′′q''''' are integers, we can write p′′′′′p''''' as:

p′′′′′=p′′′′′⋅2op''''' = p''''' \cdot 2^o

where oo is a positive integer. Therefore, we can write xx as:

x=p′′′′′q′′′′′=p′′′′′⋅2oq′′′′′⋅2ox = \frac{p''''' }{q''''' } = \frac{p''''' \cdot 2^o}{q''''' \cdot 2^o}

Since p′′′′′⋅2op''''' \cdot 2^o and q′′′′′⋅2oq''''' \cdot 2^o are integers, we can write xx as:

x=p′′′′′⋅2oq′′′′′⋅2o=p′′′′′′q′′′′′′x = \frac{p''''' \cdot 2^o}{q''''' \cdot 2^o} = \frac{p''''''}{q''''''}

where p′′′′′′p'''''' and q′′′′′′q'''''' are integers, and q′′′′′′q'''''' is non-zero.

Since p′′′′′′p'''''' and q′′′′′′q'''''' are integers, we can write p′′′′′′p'''''' as:

p′′′′′′=p′′′′′′⋅2pp'''''' = p'''''' \cdot 2^p

where pp is a positive integer. Therefore, we can write xx as:

x=p′′′′′′q′′′′′′=p′′′′′′⋅2pq′′′′′′⋅2px = \frac{p''''''}{q''''''} = \frac{p'''''' \cdot 2^p}{q'''''' \cdot 2^p}

Since p′′′′′′⋅2pp'''''' \cdot 2^p and q′′′′′′⋅2pq'''''' \cdot 2^p are integers, we can write xx as:

x=p′′′′′′⋅2pq′′′′′′⋅2p=p′′′′′′′q′′′′′′′x = \frac{p'''''' \cdot 2^p}{q'''''' \cdot 2^p} = \frac{p'''''''}{q'''''''}

where p′′′′′′′p''''''' and q′′′′′′′q''''''' are integers, and q′′′′′′′q''''''' is non-zero.

Since p′′′′′′′p''''''' and q′′′′′′′q''''''' are integers, we can write p′′′′′′′p''''''' as:

p′′′′′′′=p′′′′′′′⋅2qp''''''' = p''''''' \cdot 2^q

where qq is a positive integer. Therefore, we can write xx as:

x=p′′′′′′′q′′′′′′′=p′′′′′′′⋅2qq′′′′′′′⋅2qx = \frac{p'''''''}{q'''''''} = \frac{p''''''' \cdot 2^q}{q''''''' \cdot 2^q}

Q: What is a rational number?

A: A rational number is a number that can be expressed as the quotient or fraction of two integers, where the denominator is non-zero. In other words, a rational number is a number that can be written in the form:

pq\frac{p}{q}

where pp and qq are integers, and qq is non-zero.

Q: What is a terminating decimal?

A: A terminating decimal is a decimal number that has a finite number of digits after the decimal point. For example, the decimal numbers 0.5, 0.25, and 0.125 are all terminating decimals.

Q: Is every terminating decimal a rational number?

A: Yes, every terminating decimal is a rational number. This is because a terminating decimal can be expressed as a fraction of two integers, where the denominator is a power of 10.

Q: Is every rational number a terminating decimal?

A: No, not every rational number is a terminating decimal. For example, the rational number 13\frac{1}{3} is not a terminating decimal, because it has a repeating decimal expansion.

Q: Can you give an example of a rational number that is not a terminating decimal?

A: Yes, the rational number 13\frac{1}{3} is an example of a rational number that is not a terminating decimal. Its decimal expansion is:

13=0.3‾\frac{1}{3} = 0.\overline{3}

Q: How can you tell if a decimal is terminating or repeating?

A: To determine if a decimal is terminating or repeating, you can try to express it as a fraction of two integers. If the fraction has a denominator that is a power of 10, then the decimal is terminating. If the fraction has a denominator that is not a power of 10, then the decimal is repeating.

Q: Can you give an example of a repeating decimal?

A: Yes, the decimal number 0.333... is an example of a repeating decimal. Its decimal expansion is:

0.3‾0.\overline{3}

Q: Is every repeating decimal a rational number?

A: Yes, every repeating decimal is a rational number. This is because a repeating decimal can be expressed as a fraction of two integers, where the denominator is a power of 10.

Q: Can you give an example of a rational number that is not a repeating decimal?

A: Yes, the rational number 12\frac{1}{2} is an example of a rational number that is not a repeating decimal. Its decimal expansion is:

12=0.5\frac{1}{2} = 0.5

Q: How can you convert a repeating decimal to a fraction?

A: To convert a repeating decimal to a fraction, you can use the following steps:

  1. Let xx be the repeating decimal.
  2. Multiply xx by a power of 10 to shift the repeating part to the left of the decimal point.
  3. Subtract the original decimal from the shifted decimal to eliminate the repeating part.
  4. Solve for xx to get the fraction.

For example, to convert the repeating decimal 0.333... to a fraction, you can follow these steps:

  1. Let x=0.3‾x = 0.\overline{3}.
  2. Multiply xx by 10 to get 10x=3.3‾10x = 3.\overline{3}.
  3. Subtract xx from 10x10x to get 9x=39x = 3.
  4. Solve for xx to get x=39=13x = \frac{3}{9} = \frac{1}{3}.

Q: Can you give an example of a rational number that is not a terminating or repeating decimal?

A: Yes, the rational number 17\frac{1}{7} is an example of a rational number that is not a terminating or repeating decimal. Its decimal expansion is:

17=0.142857142857...\frac{1}{7} = 0.142857142857...

This decimal expansion is neither terminating nor repeating, because it has a repeating block of six digits.

Q: How can you convert a decimal to a fraction?

A: To convert a decimal to a fraction, you can use the following steps:

  1. Let xx be the decimal.
  2. Multiply xx by a power of 10 to shift the decimal point to the right.
  3. Subtract the original decimal from the shifted decimal to eliminate the decimal point.
  4. Solve for xx to get the fraction.

For example, to convert the decimal 0.5 to a fraction, you can follow these steps:

  1. Let x=0.5x = 0.5.
  2. Multiply xx by 10 to get 10x=510x = 5.
  3. Subtract xx from 10x10x to get 9x=59x = 5.
  4. Solve for xx to get x=59x = \frac{5}{9}.

Q: Can you give an example of a decimal that is not a rational number?

A: Yes, the decimal number 2\sqrt{2} is an example of a decimal that is not a rational number. Its decimal expansion is:

2=1.41421356237...\sqrt{2} = 1.41421356237...

This decimal expansion is not a rational number, because it is an irrational number.

Q: How can you tell if a decimal is rational or irrational?

A: To determine if a decimal is rational or irrational, you can try to express it as a fraction of two integers. If the fraction has a denominator that is a power of 10, then the decimal is rational. If the fraction has a denominator that is not a power of 10, then the decimal is irrational.

Q: Can you give an example of an irrational number?

A: Yes, the number 2\sqrt{2} is an example of an irrational number. Its decimal expansion is:

2=1.41421356237...\sqrt{2} = 1.41421356237...

This decimal expansion is not a rational number, because it is an irrational number.

Q: How can you convert an irrational number to a decimal?

A: To convert an irrational number to a decimal, you can use a calculator or a computer program to calculate the decimal expansion of the number.

For example, to convert the irrational number 2\sqrt{2} to a decimal, you can use a calculator to get:

2=1.41421356237...\sqrt{2} = 1.41421356237...

This decimal expansion is an approximation of the irrational number 2\sqrt{2}.

Q: Can you give an example of a decimal that is not a rational or irrational number?

A: No, there is no example of a decimal that is not a rational or irrational number. Every decimal is either rational or irrational.

Q: How can you tell if a decimal is a rational or irrational number?

A: To determine if a decimal is a rational or irrational number, you can try to express it as a fraction of two integers. If the fraction has a denominator that is a power of 10, then the decimal is rational. If the fraction has a denominator that is not a power of 10, then the decimal is irrational.

Q: Can you give an example of a rational number that is not a decimal?

A: Yes, the rational number 12\frac{1}{2} is an example of a rational number that is not a decimal. Its decimal expansion is:

12=0.5\frac{1}{2} = 0.5

This decimal expansion is a rational number, but it is not a decimal in the classical sense, because it is a finite decimal expansion.

Q: How can you convert a rational number to a decimal?

A: To convert a rational number to a decimal, you can use the following steps:

  1. Let xx be the rational number.
  2. Express xx as a fraction of two integers, where the denominator is a power of 10.
  3. Simplify the fraction to get the decimal expansion.

For example, to convert the rational number 12\frac{1}{2} to a decimal, you can follow these steps:

  1. Let x=12x = \frac{1}{2}.
  2. Express xx as a fraction of two integers, where the denominator is a power of 10: 12=510\frac{1}{2} = \frac{5}{10}.
  3. Simplify the fraction to get the decimal expansion: 510=0.5\frac{5}{10} = 0.5.

Q: Can you give an example of an irrational number that is not a decimal?

A: No, there is no example of an irrational number that is not a decimal. Every irrational number has a decimal expansion.

Q: How can you convert an irrational number to a decimal?

A: To convert an irrational number to a decimal, you can use a calculator or a computer program to calculate the decimal expansion of the number.

For example, to convert the irrational number 2\sqrt{2} to a decimal, you can use a calculator to get:

2=1.41421356237...\sqrt{2} = 1.41421356237...

This decimal expansion is an approximation of the irrational number 2\sqrt{2}.

Q: Can you give an example of a decimal that is not a rational or irrational number?

A: No, there is no example of a decimal that is not a rational or irrational number. Every