Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
COMEDK2025MathematicsLimitsActual

If _ x 1 x^4-1 x-1 = _ x k x^3-k^3 x^2-k^2 , then the value of K is

Options

  1. A8
  2. B8 3
  3. C4 3
  4. D3 4

Correct answer

B. 8 3

Step-by-step solution

Evaluate the first limit: _ x 1 x^4-1 x-1 = _ x 1 (x-1)(x^3+x^2+x+1) x-1 = _ x 1 (x^3+x^2+x+1) = 1+1+1+1 = 4 . Evaluate the second limit: _ x k x^3-k^3 x^2-k^2 = _ x k (x-k)(x^2+xk+k^2) (x-k)(x+k) = _ x k x^2+xk+k^2 x+k = k^2+k^2+k^2 k+k = 3k^2 2k = 3k 2 . Equate the two limits: 4 = 3k 2 . Solve for k : 3k = 8 k = 8 3 . Answer: 8 3

Practice Limits on Quantrex Academy →

More from Limits

If _ x 0 ( p 2x + 1 - 2x x + x ) = 1 then the value of ' p ' is 2026_ x 2 ( 1 - x x ) is equal to 2026The value of _ x 3 [ 1 x-3 + 9x 27-x^3 ] is: 2026_ x 0 (1 - 2x)(3 + x) x 4x is equal to: 2026If _ x 3 ( x^2 - ax - 3b x - 3 ) = 5 , then a + b = 2026If f(x) = cases x^2 - 1 & if x 2 x + 1 & if x < 2 cases , then _ x 1 f(x) + _ x 2 f(x) = 2026_ x 4 2 2 -( x+ x)^3 1- 2 x = 2025Let [x] denote the greatest integer less than or equal to x . Then _ x 2⁺ ( [x]^3 3 - [ x 3 ]^3 )= 2025 Full Limits list All COMEDK PYQs