1. Problem statement: Prove that $\sqrt[3]{3}$ is irrational.
2. Formula and concept: A number is irrational if it cannot be expressed as a fraction $\frac{p}{q}$ where $p$ and $q$ are integers with no common factors other than 1, and $q \neq 0$.
3. Assume the opposite (for contradiction): Suppose $\sqrt[3]{3}$ is rational. Then it can be written as $\frac{p}{q}$ in lowest terms, where $p$ and $q$ are integers with no common factors.
4. Write the equation:
$$\sqrt[3]{3} = \frac{p}{q}$$
Cubing both sides gives:
$$3 = \frac{p^3}{q^3}$$
5. Multiply both sides by $q^3$:
$$3q^3 = p^3$$
6. This means $p^3$ is divisible by 3, so $p$ must be divisible by 3 (because 3 is prime).
7. Let $p = 3k$ for some integer $k$. Substitute back:
$$3q^3 = (3k)^3 = 27k^3$$
8. Simplify:
$$3q^3 = 27k^3 \implies q^3 = 9k^3$$
9. This means $q^3$ is divisible by 3, so $q$ is divisible by 3.
10. But this contradicts the assumption that $p$ and $q$ have no common factors (both divisible by 3).
11. Therefore, our initial assumption is wrong, and $\sqrt[3]{3}$ is irrational.
Is tarah se humne prove kiya ki $\sqrt[3]{3}$ irrational hai.
Cube Root 3
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