Browse Definitions:
Definition

approximate equality

Approximate equality is a concept used primarily in physics and engineering, and also occasionally in mathematics. Two quantities are approximately equal when they are close enough in value so the difference is inconsequential in practical terms. Approximate equality is symbolized by a squiggly equal sign ( ).

As an example of how approximate equality can be used in mathematics, consider the positive square root of 2 (or 2 1/2 ). This is an irrational number ; when written in decimal form, it is nonterminating and nonrepeating. Expressed to four significant digits, 2 1/2 1.414. It is possible to express it to many more significant digits, but the result will always be an approximation. Thus, to 10 significant digits, 2 1/2 1.414213562, and to 20 significant digits, 2 1/2 1.4142135623730950488. An example of an approximate equation using variables is x + y z .

In experimental physics and engineering, approximate equality is the rule, because measurements of physical quantities and phenomena are seldom exact. We might say, for example, that an incandescent lamp consumes a power P of approximately 60 watt s (60 W); then we can write P 60 W. Or we might say that the speed S of a computer-file download is approximately 38.3 kilobit s per second (kbits/sec); we would then write S 38.3 kbits/sec.

In many cases, the ordinary equality symbol (=) is used in situations where, to be rigorous, the approximate equality sign ought to be used. This is done for two reasons: first, most fonts do not include an approximate equality symbol; and secondly, many people do not know what the approximate equality symbol means.

Also see Mathematical Symbols .

This was last updated in September 2005

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • security information and event management (SIEM)

    Security information and event management (SIEM) is an approach to security management that seeks to provide a holistic view of ...

  • polymorphic virus

    A polymorphic virus is a harmful, destructive or intrusive type of malware that can change or 'morph,' making it difficult to ...

  • cyberterrorism

    According to the U.S. Federal Bureau of Investigation, cyberterrorism is any 'premeditated, politically motivated attack against ...

SearchHealthIT

  • accountable care organization (ACO)

    An accountable care organization (ACO) is an association of hospitals, healthcare providers and insurers in which all parties ...

  • patient engagement

    Patient engagement is an ideal healthcare situation in which people are well-informed about -- and motivated to be involved -- in...

  • personal health record (PHR)

    A personal health record (PHR) is a collection of health-related information that is documented and maintained by the individual ...

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close