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Tamil Nadu Board of Secondary EducationHSC Science Class 11

Show that nnnlimn→∞1+2+3+...+n3n2+7n+2=16 - Mathematics

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Question

Show that `lim_("n" -> oo) (1 + 2 + 3 + ... + "n")/(3"n"^2 + 7n" + 2) = 1/6`

Sum
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Solution

`lim_("n" -> oo) (1 + 2 + 3 + ... + "n")/(3"n"^2 + 7"n" + 2) = lim_("n" -> oo) (("n"("n" + 1))/2)/(3"n"^2 + 7"n" + 2)`

= `1/2 lim_("n" -> oo) ("n"*"n"(1 + 1/"n"))/("n"^2 (3 + (7"n")/"n"^2 + 2/"n"^2)`

= `1/2 lim_("n" -> oo) ((1 + 1/"n"))/((3 + 7/"n" + 2/"n"^2))`

= `1/2 xx ((1 + 0))/((3 + 0 + 0))`

`lim_("n" -> oo) (1 + 2 + 3 + .... + "n")/(3"n"^2 + 7"n" + 2) = 1/6`

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Chapter 9: Differential Calculus - Limits and Continuity - Exercise 9.3 [Page 111]

APPEARS IN

Samacheer Kalvi Mathematics - Volume 1 and 2 [English] Class 11 TN Board
Chapter 9 Differential Calculus - Limits and Continuity
Exercise 9.3 | Q 8. (i) | Page 111

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