Domain of a function worksheet for Precalculus
Precalculus collects the restrictions a formula carries: a square root needs a non-negative inside, and a denominator, often a quadratic to factor, cannot be zero. Every answer is written in interval notation.
Also taught in Algebra 2 and Algebra 1, each at its own level and with its own examples.
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Sigma Prep · sigmaprep.io/worksheets Name Domain of a Function Date Period State the domain in interval notation.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
Sigma Prep · sigmaprep.io/worksheets Name Domain of a FunctionAnswer keyVersion 3 Date Period State the domain in interval notation.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
How to do these
State the domain of
- Factor the bottom: x² - 7x + 10 = (x - 2)(x - 5).
- It is zero at x = 2 and at x = 5, so both are left out.
- Every other number works, which takes three intervals.
The answer is .
Where students go wrong
Stopping at one excluded value. x² - 7x + 10 factors as (x - 2)(x - 5), so the bottom is zero at both 2 and 5, and the domain needs three intervals, not two.
Also called finding the domain, domain of a radical function or allowed input values.
What you can put on this worksheet
- The domain of a square root
- State the domain of →
- Rational, root-in-denominator and log
- State the domain of →