Gujarati
8. Sequences and Series
easy

श्रेणी $\frac{1}{2} + \frac{1}{3} + \frac{1}{6} + ........$ के $9$ पदों का योगफल है

A

$ - \frac{5}{6}$

B

$ - \frac{1}{2}$

C

$1$

D

$ - \frac{3}{2}$

Solution

(d) दी गयी श्रेणी  है, $\frac{1}{2} + \frac{1}{3} + \frac{1}{6} + ……..$

जहाँ $a = \frac{1}{2}$, सार्वअन्तर $d = – \frac{1}{6}$और $n = 9$.

$ \Rightarrow $ ${S_9} = \frac{9}{2}\left[ {2 \times \frac{1}{2} + (9 – 1)\left( { – \frac{1}{6}} \right)} \right] =  – \frac{3}{2}$.

Standard 11
Mathematics

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