What the following definition represents about the function:
$f(1+\frac{1}{n})=1$ for all integers $n$.
I thought of substituting some integers to see what this function is doing. It turns out that function takes value $1$ at $0$ and $1$ Also, for other integers, say $n=2$, the function takes value $1$ at $x=\frac{3}{2}$. Looks like this is a constant Function but then book says that this is a non constant three times differentiable function. I am not able to understand what this function will look like? Any help in understanding the nature of this function will be great. Thanks in advance.
EDIT.1 The function is defined for $R\rightarrow R$ and is non constant and three times differentiable. I am required to obtain $f''(1)$