arrow
arrow
arrow
​if ∑an\sum a_n∑an​ be an infinite series of non-negative terms and lim‾\overline{lim}lim an1/n=p{a_n^{1/n}} = pan1/n​=p, then ∑an\sum
Question

​if an\sum a_n be an infinite series of non-negative terms and lim\overline{lim} an1/n=p{a_n^{1/n}} = p, then an\sum a_n is convegent if​

A.

p<1p<1​​

B.

p1p\leq 1​​

C.

p>1p>1​​

D.

p=1p=1​​

Correct option is A

Given:an is a series with non-negative terms, and liman1/n=pUsing Cauchy’s Root Test:Let L=lim supan1/n{L<1=>Series convergesL>1=>Series divergesL=1=>Test is inconclusiveSince liman1/n=p exists, we apply directly:p<1=>an convergesAnswer: (A) p<1\textbf{Given:}\\ \quad \sum a_n \text{ is a series with non-negative terms, and } \lim a_n^{1/n} = p \\[6pt]\textbf{Using Cauchy's Root Test:} \\\text{Let } L = \limsup a_n^{1/n} \\[4pt]\begin{cases}L < 1 & \Rightarrow \text{Series converges} \\L > 1 & \Rightarrow \text{Series diverges} \\L = 1 & \Rightarrow \text{Test is inconclusive}\end{cases} \\[10pt]\text{Since } \lim a_n^{1/n} = p \text{ exists, we apply directly:} \\p < 1 \Rightarrow \sum a_n \text{ converges} \\[10pt]\boxed{\text{Answer: (A) } p < 1}​​

Free Tests

Free
Must Attempt

UPTET Paper 1: PYP Held on 23rd Jan 2022 (Shift 1)

languageIcon English
  • pdpQsnIcon150 Questions
  • pdpsheetsIcon150 Marks
  • timerIcon150 Mins
languageIcon English
Free
Must Attempt

UPTET Paper 2 Social Science : PYP Held on 23rd Jan 2022 (Shift 2)

languageIcon English
  • pdpQsnIcon150 Questions
  • pdpsheetsIcon150 Marks
  • timerIcon150 Mins
languageIcon English
Free
Must Attempt

UPTET Paper 2 Maths & Science : PYP Held on 23rd Jan 2022 (Shift 2)

languageIcon English
  • pdpQsnIcon150 Questions
  • pdpsheetsIcon150 Marks
  • timerIcon150 Mins
languageIcon English
test-prime-package

Access ‘WB SLST’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
students-icon
354k+ students have already unlocked exclusive benefits with Test Prime!
Our Plans
Monthsup-arrow