Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
KVPY2020MathematicsFunctions

Let x be the greatest integer less than or equal to x , for a real number x . Then the following sum 2 2020 + 1 2 2018 + 1 + 3 2020 + 1 3 2018 + 1 + 4 2020 + 1 4 2018 + 1 + 5 2020 + 1 5 2018 + 1 + 6 2020 + 1 6 2018 + 1 is :-

Options

  1. A80
  2. B85
  3. C90
  4. D95

Correct answer

B. 85

Step-by-step solution

2 2020 + 1 2 2018 + 1 = 4 . 2 2018 + 1 2 2018 + 1 = 4 2 2018 + 1 - 3 2 2018 + 1 4 - 3 2 2018 + 1 = t ,   3 < t < 4 Now 2 2020 + 1 2 2018 + 1 = 3 similarly 3 2020 + 1 3 2018 + 1 = 9 . 3 2018 + 1 3 2018 + 1 = 9 - 8 3 2018 + 1 3 2020 + 1 3 2018 + 1 = 8 similarly n 2020 + 1 2 2018 + 1 = n 2 - 1 2 2 - 1 + 3 2 - 1 + 4 2 - 1 + 5 2 - 1 + 6 2 - 1 = 3 + 8 + 15 + 24 + 35 = 85

Practice Functions on Quantrex Academy →

More from Functions

If f : R A , defined by f ( x )= x + 3 x -1 , is an onto function then A = 2025Let g(x)=1+x-[x] and f(x)= cases -1, & x 0 cases ([x] ) denotes the greatest integer less than or equal to (x ). Then for all x , f ( g ( x ))= 2025The domain of the real valued function f(x)= 3 4-x^2 + ₁₀ (x^3-x ) is 2025A real valued function f: A B defined by f(x)= 4-x^2 4+x^2 x A is a bijection. If -4 A then A B= 2025Let [ x ] represent the greatest integer less than or equal to x , x = x -[ x ] , 2 =1.414 and 3 =1.732 . If f(x)= x+ [ x 1+x^2 ] is a real valued function, then f ( 2 )+ f (- 3 )= 2025If the range of the function f(x)=-3 x-3 is 3,-6,-9,-18 , then which one of the following is not in the domain of f ? 2025The domain of the function f(x)= _e ( 1 x^2-4 x+4 ) + ⁻¹ (x^2-2 ) is 2025Consider the following statements Statement-I : A function f : A B is said to be one-one if and only if f(x) f(y) x y Statement-II : A relation f: A B is said to be a function if x 2025 Full Functions list All KVPY PYQs