Mathematics

Mathematics

Problem

IF p=3−53+5p = \frac{3-\sqrt{5}}{3+\sqrt{5}} and q=3+53−5q = \frac{3+\sqrt{5}}{3-\sqrt{5}} , find value of p2+q2p^2+q^2 .
Intuitive explanation

The key insight is that pp and qq are reciprocals of each other—notice how the numerator and denominator swap between them. Rather than rationalizing each fraction separately, find p+qp + q first by combining them over a common denominator, then use the algebraic identity (p+q)2=p2+2pq+q2(p+q)^2 = p^2 + 2pq + q^2 to isolate p2+q2p^2 + q^2. This avoids messy radical arithmetic and lets the structure of the problem do the work.

Intuitive explanation

The key insight is that pp and qq are reciprocals of each other—notice how the numerator and denominator swap between them. Rather than rationalizing each fraction separately, find p+qp + q first by combining them over a common denominator, then use the algebraic identity (p+q)2=p2+2pq+q2(p+q)^2 = p^2 + 2pq + q^2 to isolate p2+q2p^2 + q^2. This avoids messy radical arithmetic and lets the structure of the problem do the work.

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