$\"\"$

In equilateral triangle all sides are equal.

Consider $\"\\small$ to be one of the side of a triangle.

Find the height of the triangle using the figure shown below.

$\"\"$

From Pythagorean theorem,

$\"\\small$

$\"\"$

$\"\"$ .

Area of a triangle is $\"\"$ .

$\"\"$

$\"\"$ .

Domain:

The area of the function is $\"\"$ .

All possible values of $\"\\small$ is domain of the function.

Area of the triangle should be a greater than zero.

$\"\"$

Therefore the domain of the function is $\"\"$ .

$\"\"$ .

The domain of the function $\"\"$ is $\"\"$ .