Let [t] be the greatest integer less than or equal to t. Then the least value of mathbfp in mathbbN for which lim_mathrmx to 0^+ left( mathrmx left( left[ frac1mathrmx right] + left[ frac2mathrmx right] + dots + left[ fracmathrmpmathrmx right] right) - mathrmx^2 left( left[ frac1mathrmx^2 right] + left[ frac2^2mathrmx^2 right] + dots + left[ frac9^2mathrmx^2 right] right) right) geq 1 is equal to

Numerical Answer Type:
Enter a numerical value Answer: 24 +4 marks

Solution & Explanation

### Related Formula lim_x to 0^+ x left[ frackx right] = k sum_k=1^n k = fracn(n+1)2, quad sum_k=1^n k^2 = fracn(n+1)(2n+1)6 ### Core Logic Using properties of Greatest Integer Function limits, as x to 0^+, fraction values diverge cleanly to continuous variable distributions: lim_x to 0^+ x left[ frackx right] = k implies sum_k=1^p k = fracp(p+1)2 Similarly, for the second block component part: lim_x to 0^+ x^2 left[ frack^2x^2 right] = k^2 implies sum_k=1^9 k^2 = frac9 times 10 times 196 = 285 ### Step 1: Setup Inequality Formulation Combine evaluated limits component parts: fracp(p+1)2 - 285 geq 1 fracp(p+1)2 geq 286 implies p(p+1) geq 572 ### Step 2: Solve for least natural number Evaluate product bounds of adjacent integers: If p = 23 implies 23 times 24 = 552 (False) If p = 24 implies 24 times 25 = 600 (True) Therefore, the least natural value of p is 24. ### Pattern Recognition Greatest Integer fractions simplify directly to standard scalar values inside limits evaluated at infinity or zero, letting you drop brackets and treat them as arithmetic sequences. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Mathematics: Limits

Reference Study Guides

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Q17 jee_main_2024_31_jan_morning Continuity Check
Let g(x) be a linear function and f(x) = begincases g(x) & , x le 0 \\ left(frac1+x2+xright)^frac1x & , x > 0 endcases is continuous at x = 0. If f'(1) = f(-1), then the value of g(3) is
  • A. frac13 log_e left(frac49e^1/3right)
  • B. frac13 log_e left(frac49right) + 1
  • C. log_e left(frac49right) - 1
  • D. log_e left(frac49e^1/3right)

Solution

### Core Logic Let g(x) = ax + b. Since f(x) is continuous at x = 0: lim_x to 0^+ f(x) = f(0) lim_x to 0 left(frac1+x2+xright)^frac1x = b As x to 0, the base approaches frac12, and exponent approaches infty. Thus, left(frac12right)^infty = 0. So, b = 0. Thus, g(x) = ax. ### Step 1: Calculate Derivative For x > 0, f(x) = left(frac1+x2+xright)^frac1x. Let y = f(x). ln y = frac1x lnleft(frac1+x2+xright) Differentiating both sides w.r.t x: frac1y y' = -frac1x^2 lnleft(frac1+x2+xright) + frac1x cdot frac2+x1+x cdot frac1(2+x) - (1+x)1(2+x)^2 y' = y left[ -frac1x^2 lnleft(frac1+x2+xright) + frac1x(1+x)(2+x) right] ### Step 2: Apply Condition At x=1, y = f(1) = frac23. f'(1) = frac23 left[ -1 lnleft(frac23right) + frac16 right] = -frac23 lnleft(frac23right) + frac19 Also f(-1) = g(-1) = -a. Given f'(1) = f(-1) implies -a = -frac23 lnleft(frac23right) + frac19. a = frac23 lnleft(frac23right) - frac19 ### Step 3: Evaluate g(3) g(3) = 3a = 2 lnleft(frac23right) - frac13 g(3) = lnleft(frac49right) - frac13 = lnleft(frac49right) - ln(e^1/3) = lnleft(frac49e^1/3right) ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Maths: Continuity and Differentiability Class 12 Maths: Application of Derivatives

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