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Question : 18 of 160
Marks:
+1,
-0
Solution:
1+‌+‌+‌+...+∞We know that
(1+x)n=1+nx‌+‌x2‌+‌x3+...On comparing with given expansion, we get
nx=‌⇒x=‌and
‌x2=‌=‌=‌Using Eq. (i),
‌(‌)2=‌‌⇒‌‌‌×‌‌⇒‌‌‌×‌ ‌‌‌=‌‌‌‌n=‌‌‌ Also, ‌x=‌(‌)=‌‌∴‌‌(1+x)n‌=(1−‌)−2∕3‌=(‌)−2∕3=(‌)2∕3
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