Domain and Range Practice Problems
Two lessons feed this set: Domain and Range. They are practised together because exam questions almost always ask for both off the same function, and the contrast is what makes each one stick.
How to use this set
The two halves work differently, and it is worth being conscious of which one you are doing.
Domain is subtractive: start from all real numbers and remove what breaks — a zero denominator, a negative under an even root, a non-positive logarithm argument.
Range is constructive: think about what the expression can actually produce. A square is never negative, a square root is never negative, and a parabola is capped at its vertex.
Answers go in interval notation. Every equivalent spelling is accepted, but the bracket type is checked, since that is the distinction being taught.
Common mistakes to watch for
Excluding zeros of the numerator. Only the denominator restricts the domain.
Restricting an odd root. Cube roots accept negatives.
Forgetting to flip the inequality when dividing by a negative:
Assuming a root in a denominator still allows zero. It does not — that tightens
Copying the domain as the range. They are usually different intervals.
Using only the endpoints on a restricted domain. Check for a turning point inside it.
Where to go next
Interval Notation drills the bracket conventions on their own. Function Notation is the evaluation skill underneath, and Function Operations asks for domains of combined and composed functions.