Questions in fun-lim

Select	Question
	Let $f(x) = \begin{cases} \frac{1}{2},\;if\;0 \le x \le \frac{1}{2}\\ \frac{1}{3},\;if\;\frac{1}{2} < x \le 1 \end{cases}$, then $f$ is
	Function $f:R\to R,\ f(x)={{x}^{2}}+x$ is
	Mapping $f:R\to R$ which is defined as $f(x)=\cos x,\ x\in R$ will be
	The function $f:R\to R$ defined by $f(x)=(x-1)$ $(x-2)(x-3)$ is
	If $f:R\to R$, then $f(x)=\ \|x\|$ is
	Which of the four statements given below is different from others
	Let $f:N\to N$ defined by $f(x)={{x}^{2}}+x+1$, $x\in N$, then f is
	Let X and Y be subsets of R, the set of all real numbers. The function $f:X\to Y$defined by $f(x)={{x}^{2}}$ for $x\in X$ is one-one but not onto if (Here ${{R}^{+}}$ is the set of all positive real numbers)
	Set A has 3 elements and set B has 4 elements. The number of injection that can be defined from A to B is
	Let $f:R\to R$ be a function defined by $f(x)=\frac{x-m}{x-n}$, where $m\ne n$. Then