If the sets $A$ and $B$ are defined as $A = \{ (x,\,y):y = {e^x},\,x \in R\} $; $B = \{ (x,\,y):y = x,\,x \in R\} ,$ then

Let $\mathrm{X}=\{\mathrm{n} \in \mathrm{N}: 1 \leq \mathrm{n} \leq 50\} .$ If $A=\{n \in X: n \text { is a multiple of } 2\}$ and $\mathrm{B}=\{\mathrm{n} \in \mathrm{X}: \mathrm{n} \text { is a multiple of } 7\},$ then the number of elements in the smallest subset of $X$ containing both $\mathrm{A}$ and $\mathrm{B}$ is

Find the union of each of the following pairs of sets :

$A=\{1,2,3\}, B=\varnothing$

If $\mathrm{R}$ is the set of real numbers and $\mathrm{Q}$ is the set of rational numbers, then what is $\mathrm{R – Q} ?$

Find the union of each of the following pairs of sets :

$X =\{1,3,5\} \quad Y =\{1,2,3\}$