Let f:R→R be such that f(1) = 3 and f' (1) = 6.Then limx→0 f(1+x)f(1)1/x equals.
1
e1/2
e2
e3
We have,
limx→0 f(1+x)f(1)1/x=limx→0 1+f(1+x)−f(1)f(1)1/x=elimx→0 f(1+x)−f(1)xf(1)=e1f(1)limx→0 f(x+i)−f(1)x=ef′(1)f(1)=e6/3=e2 ∵limx→0 f(1+x)−f(1)x=f′(1)