List of top Mathematics Questions on Functions asked in AIEEE

For real $x,$ let $f (x) = x^3 + 5x + 1,$ then

Let W denote the words in the English dictionary. Define the relation $R $ by : $R =\{ (x,y), \in\, W \times \,W$ : the words $x$ and $y$ have at least one letter in commona$\}$ Then R is