NDA2016MathematicsLimitsActual
Paragraph: Let f(x)=[x] , where [.] is the greatest integer function and g(x)= x be two real valued functions over R . Question: Which one of the following statements is correct?
Options
- A_ x 0 (f o g)(x) exists
- B_ x 0 ( gof )(x) exists
- C_ x 0+ (f g)(x)= _ x 0- ( gof )(x)
- D_ x 0+ (f o g)(x)= _ x 0+ (g o f)(x)
Correct answer
D. _ x 0+ (f o g)(x)= _ x 0+ (g o f)(x)
Step-by-step solution
aligned & (f g)(x)=[ x] & _ x 0⁺ (f o g)(x)= _ x 0⁺ [ x]=[h] where h 0 & _ x 0⁺ (f o g)(x)=0 & _ x 0⁻ (f g)(x)= _ x 0⁻ [ x]=[h] where h 0 & _ x 0⁻ (f o g)(x)=-1 & _ x 0 (f o g)(x) does not exist. aligned Now, (g o f)(x)= [x] aligned & _ x 0⁺ (g o f)(x)= _ x 0⁺ [x]= 0=0 & _ x 0⁻ (g o f)(x)= _ x 0⁻ [x]= (-1)=-0.01745 & _ x 0 (g o f)(x) does not exist. & _ x 0⁺ (f o g)(x)= _ x 0⁺ (g o f)(x) aligned