Excluded value

Definition

A value that a variable cannot take because it would make an original denominator zero or a divisor equal to zero.

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Specification A4 · Paper 1, Paper 2, Paper 3

A value that a variable cannot take because it would make an original denominator zero or make another operation undefined.
Every denominator must be non-zero, so begin by recording any excluded values.
Revise: Surds and Algebraic Fractions

Specification A4 · Paper 1, Paper 2, Paper 3

1
State excluded values when simplifying an algebraic fraction; cancellation does not make an originally undefined value valid.
2
State excluded values from the original denominators. A factor that cancels still gives a value that was forbidden in the original expression.
3
State excluded values when requested. A value excluded by the original denominator remains excluded even if its factor later cancels.

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This is an excluded value.

Specification 6.01g · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)

A value that a variable cannot take because it would make an original denominator zero or make a division invalid.
Revise: Algebraic Fraction Operations