Let a_1, a_2, ldots ldots, a_n be in A.P. If | vedclass

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Question

$2 a_7=a_s(	ext { given })$

$2\left(a_1+6 dight)=a_1+4 d$

$a_1+8 d=0$

$a_1+10 d=18$

$	ext { By }(1) 	ext { and }(2) 	ext { we get }

Vedclass · Accepted Answer

$8$

Vedclass · Answer

$2 a_7=a_s(	ext { given })$

$2\left(a_1+6 dight)=a_1+4 d$

$a_1+8 d=0$

$a_1+10 d=18$

$	ext { By }(1) 	ext { and }(2) 	ext { we get } a_1=-72, d=9$

$a_{18}=a_1+17 d=-72+153=81$

$a_{10}=a_1+9 d=9$

$12\left(\frac{\sqrt{a_{11}}-\sqrt{a_{10}}}{d}+\frac{\sqrt{a_{12}}-\sqrt{a_{11}}}{d}+\ldots . . \frac{\sqrt{a_{18}}-\sqrt{a_{17}}}{d}ight)$

$12\left(\frac{\sqrt{a_{18}}-\sqrt{a_{10}}}{d}ight)=\frac{12(9-3)}{9}=\frac{12 	imes 6}{6}=8$

Let $a_1, a_2, \ldots \ldots, a_n$ be in A.P. If $a_5=2 a_3$ and $a_{11}=18$, then $12\left(\frac{1}{\sqrt{a_{10}}+\sqrt{a_{11}}}+\frac{1}{\sqrt{a_{11}}+\sqrt{a_{12}}}+\ldots . \cdot \frac{1}{\sqrt{a_{17}}+\sqrt{a_{18}}}\right)$ is equal to $..........$.

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