,

Replace the function designators with the actual functions in .

Simplify.

To write as a fraction with a common denominator, multiply by .

Combine the numerators over the common denominator.

Set the radicand in greater than or equal to to find where the expression is defined.

Add to both sides of the inequality.

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Set the denominator in equal to to find where the expression is undefined.

The domain is all values of that make the expression defined.

Interval Notation:

Set-Builder Notation:

Find the Domain of the Sum f(x) = square root of 4x-1 , g(x)=1/x