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Mathematics vocabulary · Proofs and Mathematical Writing

Let x be

Meaning in mathematics, with examples

phraseCore term

In mathematics, let x be means: A fixed phrase used to introduce a variable or an assumption at the start of a solution or proof, as in 'Let x be the number of tickets sold'.

In Turkish: x ... olsun

How it is used

Found in every textbook and proof. Common forms are 'Let x be a real number', 'Let n be an even integer' and 'Let ABC be a triangle'. Similar openings include 'Let x = …', 'Suppose that…' and 'Assume that…'.

Example sentences

  1. Let x be the width of the rectangle; then its length is x + 4.

  2. Let n be any odd integer, so n = 2k + 1 for some integer k.

Common collocations

  • let x be
  • let n be an integer
  • let ABC be a triangle
  • let x equal
  • variableA letter or symbol, such as x or y, that stands for a number which can change or which you do not know yet.
  • proofA logical argument that shows, step by step from accepted facts, that a mathematical statement is always true.
  • it follows thatA linking phrase used in proofs and solutions to show that the next statement is a logical result of what has just been shown.
  • without loss of generalityA phrase in proofs meaning that only one case is treated because the other cases work in exactly the same way, as in 'assume a ≤ b'.

More terms: Proofs and Mathematical Writing

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