ABC26GN1436 · Square Roots and Cube Roots
Subject: General Aptitude · Chapter: Square Roots and Cube Roots · Exam: 2011 · Marks: · Difficulty:
The expression $1-\frac{1}{1+\sqrt{3}}+\frac{1}{1-\sqrt{3}}$ equals
(a)$1-\sqrt{3}$
(b)1
(c)$-\sqrt{3}$
(d)$\sqrt{3}$
Answer
Explanation
Given $\exp .=\frac{(1+\sqrt{3})(1-\sqrt{3})-(1-\sqrt{3})+(1+\sqrt{3})}{(1+\sqrt{3})(1-\sqrt{3})}$ $$\begin{aligned} & =\frac{1-(\sqrt{3})^{2}-1+\sqrt{3}+1+\sqrt{3}}{1^{2}-(\sqrt{3})^{2}} \\ & =\frac{2 \sqrt{3}-2}{1-3}=\frac{2(\sqrt{3}-1)}{(-2)}=1-\sqrt{3} . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.
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