SOLUTION: Also, do you have a subheading for finding the domain of a function?

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Question 26627: Also, do you have a subheading for finding the domain of a function?
Answer by AnlytcPhil(1810)   (Show Source): You can put this solution on YOUR website!
Also, do you have a subheading for finding the domain of a function?

If your function is defined with an ordinary algebraic expression:

Case 1:

The expression for f(x) contains
(1) no denominator containing variables.
(2) no radical with an even index containing variables.

Th domain is always (-oo, oo)

Case 2:
(1) there is a denominator containing a variable.
(2) there is no radical with an even index containing variables

Find all real zeros of the denominator.  If any, these numbers must
be singly ruled out of the domain. 

Suppose the denominator has zeros, say -4 and +3. Then domain is

        (-oo, -4) U (-4, 3) U (3, oo)

Case 3:
(1) there is a radical with an even index containing variables
(2) there is no denominator containing variables

Set the radicand >= 0 and solve for x

Suppose you get x >= 5. Then domain is

         [5, oo}

If the radical with even root is itself a denominator then domain is

         (5, oo)

If your functions are simple the above will take care of them.


Edwin
AnlytcPhil@aol.com

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