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Zorluk: OrtaSurds and Rationalization of Denominators

If 6+262=p+q3\frac{\sqrt{6} + \sqrt{2}}{\sqrt{6} - \sqrt{2}} = p + q\sqrt{3}, where pp and qq are rational numbers, what is the value of p+qp + q?

  1. A
    1
  2. B
    2
  3. 3Cevap
  4. D
    5

Cevap

The value of p+qp + q is 3.
Multiplying both numerator and denominator by the conjugate (6+2)(\sqrt{6} + \sqrt{2}) yields 8+434=2+3\frac{8 + 4\sqrt{3}}{4} = 2 + \sqrt{3}. Matching terms with p+q3p + q\sqrt{3} gives p=2p = 2 and q=1q = 1, so p+q=3p + q = 3.

Adım Adım Çözüm

1
Multiply the numerator and denominator by the conjugate of the denominator, (6+2)(\sqrt{6} + \sqrt{2}).
(6+2)(6+2)(62)(6+2)\frac{(\sqrt{6} + \sqrt{2})(\sqrt{6} + \sqrt{2})}{(\sqrt{6} - \sqrt{2})(\sqrt{6} + \sqrt{2})}
To eliminate radicals from the denominator.
2
Expand both numerator and denominator.
Numerator: 6+212+2=8+436 + 2\sqrt{12} + 2 = 8 + 4\sqrt{3}. Denominator: 62=46 - 2 = 4.
Using algebraic expansion (a+b)2=a2+2ab+b2(a+b)^2 = a^2 + 2ab + b^2 and difference of two squares.
3
Simplify the resulting fraction.
8+434=2+3\frac{8 + 4\sqrt{3}}{4} = 2 + \sqrt{3}
Dividing each term in the numerator by 4.
4
Equate to p+q3p + q\sqrt{3} to determine pp and qq, then find p+qp + q.
p=2p = 2, q=1    p+q=2+1=3q = 1 \implies p + q = 2 + 1 = 3.
Comparing rational and irrational parts separately.

Anahtar Kavram

Rationalization of Denominators and Surd Conjugates
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