The function is .

Observe the graph: 

Observe the graph:

At , the value is .

The function is .

Domain :

The value under the square root should not be negative.

The expression  should be zero or positive.

The Denominator of any function should not be zero.

The Denominator is zero at

So domain does not exist at

Domain =

Graphically the value of the function exist at .

Analytically the value of the function does not exists.

That is the advantage of calculating domain analytically.

Domain .

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