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NDA Mathematics Limits 2026 NDA 2026 (Phase 1)

NDA Mathematics Question (2026) — Solution

Question

What is _ x 1 x^ (n^2-1) -1 x^ (n+1) -1 equal to, where n>1 is a natural number ?

Options

  1. A. 0
  2. B. 1
  3. C. n-1
  4. D. n+1

Answer

C. n-1

Step-by-step solution

The given limit is _ x 1 x^ (n^2-1) -1 x^ (n+1) -1 . As x 1, the expression takes the indeterminate form 0 0 . Applying L'Hospital's rule, we differentiate the numerator and the denominator with respect to x: _ x 1 (n^2-1)x^ n^2-2 (n+1)x^n Substituting x=1, we get: n^2-1 n+1 (n-1)(n+1) n+1 n-1 Answer: n-1

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