If $$f: R \rightarrow R$$ be defined by

$$f(x)=\left\{\begin{array}{llc} 2 x: & x>3 \\ x^2: & 1< x \leq 3 \\ 3 x: & x \leq 1 \end{array}\right.$$

then $$f(-1)+f(2)+f(4)$$ is

Domain of $$f(x)=\frac{x}{1-|x|}$$ is

$$f: R \rightarrow R$$ defined by $$f(x)$$ is equal to $$\left\{\begin{array}{l}2 x, x> 3 \\ x^2, 1< x \leq 3, \text { then } f(-2)+f(3)+f(4) \text { is } \\ 3 x, x \leq 1\end{array}\right.$$

Let $$A=\{x: x \in R, x$$ is not a positive integer) Define $$f: A \rightarrow R$$ as $$f(x)=\frac{2 x}{x-1}$$, then $$f$$ is