Question

If $A=\{1,2,3,4,5\}$, then find the domain in the relation from $A\to A$ by $R=\left\{(x,y):y=2x-1\right\}.$

• A. $\{1,2,3\}$
• B. $\{1,2\}$
• C. $\{1,3,5\}$
• D. $\{2,4\}$

Answer 1

The correct option is A

$\{1,2,3\}$

Explanation for the correct option:

Finding domain

Given,$y=2x-1$

At, $x=1,$

Then, $y=1$

At $x=2,$

Then, $y=3$

At, $x=3,$

Then, $y=5$

When $A\to A$

$\{1,2,3,4,5,\}\to \{1,2,3,4,5\}$

And the order pairs are $(1,1),(2,3),(3,5)$

The coordinates of ‘x’ are $\{1,2,3\}$ is the domain.

Hence, the correct option is $\left(A\right)$.