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Exercise 267Logic, sets and proofs › Quantifiers and negationHigh schoolAdded 3 Nov 2026

The existential quantifier

#existential quantifier#exists#example

Statement

Write in formal notation: "There exists an integer nn such that n2=4n^2=4." Determine its truth value.

Hint

Use ∃\exists for "there exists".

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Solution

Formal notation. ∃n∈Z, n2=4\exists n\in\mathbb{Z},\ n^2=4.

Truth value. True: n=2n=2 (or n=−2n=-2) satisfies n2=4n^2=4.

Conclusion. The statement is true.