Concept-wise Practice

irrational proof MCQ Questions for Class 10

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Practice Questions

4 questions tagged with irrational proof.

यदि (p) और (q) शून्येतर परिमेय संख्याएं हैं और \(p+q\sqrt{3}=0\), तो कौन सा निष्कर्ष सही है?

If (p) and (q) are non-zero rational numbers and \(p+q\sqrt{3}=0\), which conclusion is correct?

Explanation opens after your attempt
Correct Answer

A. \(\sqrt{3}=-\frac{p}{q}\) होगा जो असंभव है\(\sqrt{3}=-\frac{p}{q}\) would be true which is impossible

Step 1

Concept

\(-\frac{p}{q}\) is rational so it would make \(\sqrt{3}\) rational which is false. In exams recognize the contradiction method.

Step 2

Why this answer is correct

The correct answer is A. \(\sqrt{3}=-\frac{p}{q}\) होगा जो असंभव है / \(\sqrt{3}=-\frac{p}{q}\) would be true which is impossible. \(-\frac{p}{q}\) is rational so it would make \(\sqrt{3}\) rational which is false. In exams recognize the contradiction method.

Step 3

Exam Tip

\(-\frac{p}{q}\) परिमेय है इसलिए इससे \(\sqrt{3}\) परिमेय हो जाएगा जो गलत है। परीक्षा में विरोधाभास विधि पहचानें।

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यदि (p) और (q) शून्येतर परिमेय संख्याएं हैं और \(p+q\sqrt{2}=0\), तो कौन सा निष्कर्ष सही है?

If (p) and (q) are non-zero rational numbers and \(p+q\sqrt{2}=0\), which conclusion is correct?

Explanation opens after your attempt
Correct Answer

A. \(\sqrt{2}=-\frac{p}{q}\), इसलिए \(\sqrt{2}\) परिमेय होगा जो असंभव है\(\sqrt{2}=-\frac{p}{q}\), so \(\sqrt{2}\) would be rational which is impossible

Step 1

Concept

Since \(-\frac{p}{q}\) is rational, this would make \(\sqrt{2}\) rational which is false. In exams recognize the contradiction method.

Step 2

Why this answer is correct

The correct answer is A. \(\sqrt{2}=-\frac{p}{q}\), इसलिए \(\sqrt{2}\) परिमेय होगा जो असंभव है / \(\sqrt{2}=-\frac{p}{q}\), so \(\sqrt{2}\) would be rational which is impossible. Since \(-\frac{p}{q}\) is rational, this would make \(\sqrt{2}\) rational which is false. In exams recognize the contradiction method.

Step 3

Exam Tip

क्योंकि \(-\frac{p}{q}\) परिमेय है, इससे \(\sqrt{2}\) परिमेय मानना पड़ेगा जो गलत है। परीक्षा में विरोधाभास विधि को पहचानें।

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कौन सा विकल्प बताता है कि \(\sqrt{2}+\sqrt{8}\) अपरिमेय है?

Which option shows that \(\sqrt{2}+\sqrt{8}\) is irrational?

Explanation opens after your attempt
Correct Answer

A. यह \(3\sqrt{2}\) हैIt is \(3\sqrt{2}\)

Step 1

Concept

\(\sqrt{8}=2\sqrt{2}\), so the sum is \(3\sqrt{2}\). A non zero rational multiple of \(\sqrt{2}\) remains irrational.

Step 2

Why this answer is correct

The correct answer is A. यह \(3\sqrt{2}\) है / It is \(3\sqrt{2}\). \(\sqrt{8}=2\sqrt{2}\), so the sum is \(3\sqrt{2}\). A non zero rational multiple of \(\sqrt{2}\) remains irrational.

Step 3

Exam Tip

\(\sqrt{8}=2\sqrt{2}\), इसलिए योग \(3\sqrt{2}\) है। गैर शून्य परिमेय गुणक के साथ \(\sqrt{2}\) अपरिमेय रहता है।

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यदि (p) और (q) सहअभाज्य धनात्मक पूर्णांक हैं और \(\sqrt{3}=\frac{p}{q}\) मान लिया जाए, तो प्रमाण में कौन-सा विरोध मिलेगा?

If (p) and (q) are coprime positive integers and \(\sqrt{3}=\frac{p}{q}\) is assumed, what contradiction appears in the proof?

Explanation opens after your attempt
Correct Answer

A. (p) और (q) दोनों (3) से विभाज्य निकलते हैंBoth (p) and (q) turn out divisible by (3)

Step 1

Concept

Assuming \(\sqrt{3}=\frac{p}{q}\) gives \(p^2=3q^2\).

Step 2

Why this answer is correct

This makes both (p) and (q) divisible by (3), contradicting that they are coprime.

Step 3

Exam Tip

In such proofs, finding a common factor creates the contradiction. चरण 1: \(\sqrt{3}=\frac{p}{q}\) मानने पर \(p^2=3q^2\) मिलता है। चरण 2: इससे (p) और फिर (q) दोनों (3) से विभाज्य निकलते हैं, जबकि वे सहअभाज्य माने गए थे। चरण 3: ऐसे प्रमाण में समान गुणनखंड मिलना ही विरोध बनाता है।

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