What the Domain Is
Part of the Functions & Transformations section of Coddy's Algebra 2 journey. Lesson 11 of 58.
The domain of a function is the set of inputs it accepts. For a rule like 2x + 5, every real number works, so the domain is all real numbers.
Some rules refuse certain inputs. f(x) = 1/x has no output at 0, because dividing by zero is undefined. g(x) = √(x) has no real output for a negative input, because no real number squares to a negative. Those inputs are outside the domain.
So finding a domain is a hunt for trouble: look for a division that could hit zero and a square root that could see a negative. For the rules in this section, everything else is allowed.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Functions & Transformations
4Combining Functions
Adding FunctionsSubtracting FunctionsMultiplying FunctionsAt a Single NumberRecap: Combining10Functions in Stories
Writing the RuleUsing the RuleWorking BackwardUndoing a ConversionRecap: Stories2Expressions as Inputs
A Letter as InputA Sum as InputShifting the InputSolving f(x) = kRecap: Inputs as Expressions5Composition
One Inside AnotherOrder MattersA Function of ItselfComposing RulesBreaking ApartRecap: Composition8Stretching and Flipping
Taller and FlatterFlipping OverFlip, Then ShiftReading the RuleRecap: Stretch and Flip