Update

Muft Shiksha™ एक 100% Free Education Portal है 🇮🇳, जिसका उद्देश्य Class 9–12 के हर विद्यार्थी तक High-Quality Education को पूरी तरह मुफ्त पहुँचाना है। 🇮🇳 हम मानते हैं कि अच्छी शिक्षा किसी student की आर्थिक स्थिति पर निर्भर नहीं होनी चाहिए। 🇮🇳 हर विद्यार्थी को वही Quality Study Material, MCQs, Quizzes, Exam Preparation, Concept-Based Learning और Bilingual Support मिलना चाहिए, जो आमतौर पर महंगी Coaching या Premium Platforms में मिलता है। Muft Shiksha™ 🇮🇳 इसी सोच के साथ बनाया गया है

Subjects
0 reads0 ratings0 helpful

If (p=8-\sqrt{63}), what is the value of (\frac{1}{p}-p)?

Answer and explanation

Correct answer: (2\sqrt{63})

The direct answer is option A, 2\sqrt{63}. Let p=8-\sqrt{63}. Rationalize its reciprocal by multiplying numerator and denominator by the conjugate 8+\sqrt{63}: 1/p=(8+\sqrt{63})/(8^2-(\sqrt{63})^2)=(8+\sqrt{63})/(64-63)=8+\sqrt{63}. Therefore 1/p-p=(8+\sqrt{63})-(8-\sqrt{63})=2\sqrt{63}. Option A is correct. Option B, 16, incorrectly adds or otherwise combines the constants while losing the radical terms. Option C, \sqrt{63}, misses the second radical; subtraction produces two copies of it. Option D, 8\sqrt{63}, introduces an extra factor of 4 and does not follow from the algebra. It is also useful to notice that p is nonzero because 8^2-63=1, so the reciprocal exists. The conjugate method works because (u-v)(u+v)=u^2-v^2. The supplied answer and explanation are mathematically consistent.

Related tags

RationalizationConjugatesReal Numbers

Was this question useful?

No ratings yetWrite a review / Rate this question

Student Reviews

No published reviews yet.

Add Muft Shiksha to your Home Screen

In Safari, tap Share, then Add to Home Screen.