Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
AP EAMCET202316 May 2023Evening ShiftMathematicsFunctionsActual

If f : R R is defined by f ( x + y )= f ( x )+ f ( y ) x , y R and f(1)=7 , then _ r=1 ^n f(r)=

Options

  1. A3 n(n+2) 4
  2. Bn ( n -1) 2
  3. C7 n(n+1) 2
  4. D( n +1)( n +2) 4

Correct answer

C. 7 n(n+1) 2

Step-by-step solution

Since f(x+y)=f(x)+f(y), x, y R f(x)=a x where a R Since given, f (1)=7 7= a 1 a =7 f ( x )=7 x Now, _ r =1 ^ n f ( r )= _ r =1 ^ n 7 r = 7 n ( n +1) 2

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 AP EAMCET PYQs