Prove that the product of the two rational numbers 36−−√

and 5/3
is a rational number. Find the product and explain how you know it is a rational number. Explain your reasoning in 1–2 sentences.

11 answers

To prove that the product of \( \sqrt{36} \) and \( \frac{5}{3} \) is a rational number, we first calculate the product.

\[ \sqrt{36} = 6 \]

Now, we find the product:

\[ 6 \times \frac{5}{3} = \frac{6 \times 5}{3} = \frac{30}{3} = 10 \]

Since \( 10 \) is a whole number, it is also a rational number (all integers are rational as they can be expressed as a fraction with a denominator of 1). Thus, the product of \( \sqrt{36} \) and \( \frac{5}{3} \) is a rational number.

please in simple sentences

The square root of 36 is 6. When we multiply 6 by \( \frac{5}{3} \), we get \( 10 \), which is a whole number. Since 10 can be written as \( \frac{10}{1} \), it is a rational number. Therefore, the product of \( \sqrt{36} \) and \( \frac{5}{3} \) is a rational number.

Prove that the sum of 34
and 10−−√
is irrational. Show your work, and in 1–2 sentences, explain why the sum is an irrational number.

To prove that the sum of \( 34 \) and \( \sqrt{10} \) is irrational, we can assume the opposite — that their sum is rational — and reach a contradiction.

  1. Assume the Sum is Rational: Let’s assume \( 34 + \sqrt{10} \) is rational. This means \( 34 + \sqrt{10} = r \) for some rational number \( r \).

  2. Isolate the Square Root: Rearranging gives us: \[ \sqrt{10} = r - 34 \] Since \( r \) is rational and \( 34 \) is also rational, the difference \( r - 34 \) is rational.

  3. Rationality of the Square Root: This implies that \( \sqrt{10} \) is rational (as it equals a rational number).

  4. Contradiction: However, it is known that \( \sqrt{10} \) is an irrational number (because 10 is not a perfect square), which contradicts our assumption that \( 34 + \sqrt{10} \) is rational.

Therefore, since our assumption led to a contradiction, we conclude that \( 34 + \sqrt{10} \) must be irrational.

Explanation:

The sum \( 34 + \sqrt{10} \) is irrational because it combines a rational number (34) with an irrational number (\( \sqrt{10} \)), and the sum of a rational and an irrational number is always irrational.

Prove that the sum of 3/4
and 10−−√
is irrational. Show your work, and in 1–2 sentences, explain why the sum is an irrational number.

To prove that the sum of \( \frac{3}{4} \) and \( \sqrt{10} \) is irrational, we will assume the opposite and arrive at a contradiction.

  1. Assume the Sum is Rational: Let’s assume \( \frac{3}{4} + \sqrt{10} \) is rational. This means there exists a rational number \( r \) such that: \[ \frac{3}{4} + \sqrt{10} = r \]

  2. Isolate the Square Root: Rearranging gives us: \[ \sqrt{10} = r - \frac{3}{4} \] Since \( r \) is rational and \( \frac{3}{4} \) is also rational, the difference \( r - \frac{3}{4} \) is rational.

  3. Rationality of the Square Root: This means that \( \sqrt{10} \) is rational, as it equals a rational number.

  4. Contradiction: However, it is known that \( \sqrt{10} \) is irrational (because 10 is not a perfect square), which contradicts our previous conclusion that \( \sqrt{10} \) can be expressed as a rational number.

Therefore, since our assumption leads to a contradiction, we conclude that \( \frac{3}{4} + \sqrt{10} \) must be irrational.

Explanation:

The sum \( \frac{3}{4} + \sqrt{10} \) is irrational because it adds a rational number (\(\frac{3}{4}\)) to an irrational number (\(\sqrt{10}\)), and the sum of a rational and an irrational number is always irrational.

what is the sum

To find the sum of \( \frac{3}{4} \) and \( \sqrt{10} \), we can express it as follows:

\[ \frac{3}{4} + \sqrt{10} \]

Since \( \sqrt{10} \) is approximately \( 3.162 \), we can compute the sum numerically:

  1. Convert \( \frac{3}{4} \) to a decimal: \[ \frac{3}{4} = 0.75 \]

  2. Add it to the approximate value of \( \sqrt{10} \): \[ 0.75 + 3.162 \approx 3.912 \]

Thus, the sum is:

\[ \frac{3}{4} + \sqrt{10} \approx 4.912 \]

However, the exact sum remains \( \frac{3}{4} + \sqrt{10} \), which cannot be simplified further without a decimal approximation.

Prove that the product of 2π
and 3/4
is an irrational number. Find the product and explain why the value is irrational. Explain your reasoning in 1–2 sentences.(2 points)

To prove that the product of \( 2\pi \) and \( \frac{3}{4} \) is an irrational number, we can start by calculating the product:

\[ 2\pi \times \frac{3}{4} = \frac{3 \times 2\pi}{4} = \frac{6\pi}{4} = \frac{3\pi}{2} \]

Explanation of Irrationality:

We know that \( \pi \) is an irrational number. Since the product of a non-zero rational number (\( \frac{3}{2} \)) and an irrational number (\( \pi \)) is always irrational, the product \( \frac{3\pi}{2} \) is also irrational.

Reasoning:

Thus, \( 2\pi \times \frac{3}{4} = \frac{3\pi}{2} \) is irrational because multiplying an irrational number by a non-zero rational number results in an irrational number.