1. Stating the problem: We need to separate the given real numbers into rational and irrational numbers and explain the reasoning.
2. Definition reminder:
- Rational numbers are numbers that can be expressed as the ratio of two integers, i.e., $\frac{p}{q}$ where $p,q\in \mathbb{Z}$ and $q \neq 0$.
- Irrational numbers cannot be expressed as a ratio of two integers. Their decimal expansions are non-terminating and non-repeating.
3. Analyze the given numbers:
(i) $0$ — This can be written as $\frac{0}{1}$, a rational number.
(ii) $1^{100}$ — This equals $1$, which is rational.
(iii) $100$ — An integer and hence rational.
(iv) $\sqrt{5}$ — $5$ is not a perfect square, so $\sqrt{5}$ is irrational.
(v) $\sqrt[3]{7}$ — Cube root of 7; since 7 is not a perfect cube, this is irrational.
(vi) $\sqrt{8}$ — Simplify: $\sqrt{8} = \sqrt{4 \times 2} = 2\sqrt{2}$. Since $\sqrt{2}$ is irrational, this is irrational.
(vii) $\log_{10} 10$ — Equals 1, since $10^1=10$. Rational.
(viii) $\log_2 7$ — 7 is not a power of 2, so $\log_2 7$ is irrational.
(ix) $1.\overline{2}$ — The repeating decimal $1.2222\ldots$ equals $\frac{10}{9}$, rational.
(x) $\sqrt{\frac{4}{5}}$ — This can be written as $\frac{\sqrt{4}}{\sqrt{5}} = \frac{2}{\sqrt{5}}$. Since $\sqrt{5}$ is irrational, the fraction is irrational.
(xi) $20$ — Integer, rational.
(xii) $1$ — Integer, rational.
4. Summary:
- Rational numbers: $0, 1^{100}=1, 100, \log_{10} 10=1, 1.\overline{2}, 20, 1$
- Irrational numbers: $\sqrt{5}, \sqrt[3]{7}, \sqrt{8}, \log_2 7, \sqrt{\frac{4}{5}}$
Thus, the rational numbers are those expressible as fractions or integers or repeating decimals, while the irrational ones include roots and logarithms that cannot be simplified to rational values.
Rational Vs Irrational
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