# CAT2019-1: 75

1 vote
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If $a_{1},a_{2}\dots$ are in A.P., then, $\frac{1}{\sqrt{a_{1}}+\sqrt{a_{2}}}+\frac{1}{\sqrt{a_{2}}+\sqrt{a_{3}}}+\dots+\frac{1}{\sqrt{a_{n}}+\sqrt{a_{n+1}}}$ is equal to

1. $\frac{n-1}{\sqrt{a_{1}}+\sqrt{a_{n-1}}}$
2. $\frac{n}{\sqrt{a_{1}}+\sqrt{a_{n+1}}}$
3. $\frac{n-1}{\sqrt{a_{1}}+\sqrt{a_{n}}}$
4. $\frac{n}{\sqrt{a_{1}}-\sqrt{a_{n+1}}}$

edited

498 points 1 2 5

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