Wolfram Language & System 11.0 (2016)|Legacy Documentation

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converts an approximate number x to a nearby rational with small denominator.

yields the rational number with smallest denominator that lies within dx of x.


  • Rationalize[x,dx] works with exact numbers x.
  • Rationalize[x] yields x unchanged if there is no rational number close enough to x to satisfy the condition , with chosen to be .
  • Rationalize[x,0] converts any x to rational form. »
Introduced in 1988
| Updated in 1999