The area of the rectangle  m.

But area of a rectangle is .

Where  is the length of the rectangle.

            is the breadth of the rectangle.

Find in terms of .

.

Perimeter of a rectangle is . 

Find the expression for perimeter of the rectangle in terms of .

Substitute in the above expression.

Domain :

The denominator of the function should not be a zero.

So .

But perimeter can not be a negative.

All positive real numbers of is the domain of the function .

The domain of the is .

.

The domain of the is .