Convex function and Numerical analysis: Difference between pages

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[[Image:ConvexFunction.svg|thumb|300px|right|Convex function on an interval.]]
[[Image:Ybc7289-bw.jpg|thumb|250px|right|Babylonian clay tablet YBC 7289 (c. 1800–1600 BC) with annotations. The approximation of the [[square root of 2]] is four [[sexagesimal]] figures, which is about six [[decimal]] figures. 1 + 24/60 + 51/60<sup>2</sup> + 10/60<sup>3</sup> = 1.41421296...<ref>[http://it.stlawu.edu/%7Edmelvill/mesomath/tablets/YBC7289.html Photograph, illustration, and description of the ''root(2)'' tablet from the Yale Babylonian Collection]</ref>]]'''Numerical analysis''' studies different [[algorithm]]s to get [[approximation]]s for  problems of [[mathematical analysis]]. Approximations are used for the following reasons:
[[Image:Epigraph convex.svg|right|thumb|300px|A function (in black) is convex if and only if the region above its [[graph]] (in green) is a [[convex set]].]] In [[mathematics]], a '''convex function''' is any [[function (mathematics)|function]] with value of the [[weighted average]] of 2 points is [[less than or equal to]] the weighted average of the function at those points.  Also, a function is convex [[if and only if]] its [[epigraph (mathematics)|epigraph]] is a [[convex set]].
#There are no known ways to solve a problem using calculus. Examples for such problems are the [[Navier–Stokes equations]] or the [[Three-body problem]]
#There is a way to solve a problem using calculus. Getting an exact solution is impractical though, because it requires a long time, or many resources. An example for this is calculating [[Power series]].


== Examples ==
One of the earliest known uses of numerical analysis is a [[Babylonian]] [[clay]] [[tablet]], which approximates the [[square root]] of 2. In a [[unit square]], the diagonal has this length. Being able to compute the sides of a triangle is extremely important, for instance, in [[carpentry]] and [[construction]].<ref>The New Zealand Qualification authority specifically mentions this skill in document 13004 version 2, dated 17 October 2003 titled [http://www.nzqa.govt.nz/nqfdocs/units/pdf/13004.pdf CARPENTRY THEORY: Demonstrate knowledge of setting out a building]</ref>
Three examples are:
* A [[line]]: <math>f(x) = x</math>
* A [[parabola]]: <math>f(x) = x^2</math>
* [[Absolute value]]: <math>f(x) = |x|</math>


{{Math-stub}}
Numerical analysis continues this long tradition of practical mathematical calculations. Much like the Babylonian approximation of <math>\sqrt{2}</math>, modern numerical analysis does not seek exact answers, because exact answers are often impossible to obtain in practice. Instead, much of numerical analysis is concerned with obtaining approximate solutions while maintaining reasonable bounds on errors.
[[Category:Functions and mappings]]
 
Numerical analysis naturally finds applications in all fields of engineering and the physical sciences, but in the 21st&nbsp;century, the life sciences and even the arts have adopted elements of scientific computations. Ordinary [[differential equation]]s appear in [[Proper motion|star movement]]; [[Mathematical optimization|optimization]] occurs in portfolio management; [[numerical linear algebra]] is important for data analysis; [[Probability theory|stochastic]] [[differential equation]]s and [[Markov chain]]s are essential in simulating living cells for [[medicine]] and [[biology]].
 
[[Computer]]s greatly helped this task. Before there were computers, numerical methods often depended on hand [[interpolation]] in large printed tables. Since the mid 20th century, computers calculate the required functions instead. These same interpolation formulas nevertheless continue to be used as part of the software [[algorithms]] for solving [[differential equations]].
 
==References==
{{reflist}}
 
{{math-stub}}
[[Category:Mathematics]]

Latest revision as of 18:21, 12 March 2013

File:Ybc7289-bw.jpg
Babylonian clay tablet YBC 7289 (c. 1800–1600 BC) with annotations. The approximation of the square root of 2 is four sexagesimal figures, which is about six decimal figures. 1 + 24/60 + 51/602 + 10/603 = 1.41421296...[1]

Numerical analysis studies different algorithms to get approximations for problems of mathematical analysis. Approximations are used for the following reasons:

  1. There are no known ways to solve a problem using calculus. Examples for such problems are the Navier–Stokes equations or the Three-body problem
  2. There is a way to solve a problem using calculus. Getting an exact solution is impractical though, because it requires a long time, or many resources. An example for this is calculating Power series.

One of the earliest known uses of numerical analysis is a Babylonian clay tablet, which approximates the square root of 2. In a unit square, the diagonal has this length. Being able to compute the sides of a triangle is extremely important, for instance, in carpentry and construction.[2]

Numerical analysis continues this long tradition of practical mathematical calculations. Much like the Babylonian approximation of [math]\displaystyle{ \sqrt{2} }[/math], modern numerical analysis does not seek exact answers, because exact answers are often impossible to obtain in practice. Instead, much of numerical analysis is concerned with obtaining approximate solutions while maintaining reasonable bounds on errors.

Numerical analysis naturally finds applications in all fields of engineering and the physical sciences, but in the 21st century, the life sciences and even the arts have adopted elements of scientific computations. Ordinary differential equations appear in star movement; optimization occurs in portfolio management; numerical linear algebra is important for data analysis; stochastic differential equations and Markov chains are essential in simulating living cells for medicine and biology.

Computers greatly helped this task. Before there were computers, numerical methods often depended on hand interpolation in large printed tables. Since the mid 20th century, computers calculate the required functions instead. These same interpolation formulas nevertheless continue to be used as part of the software algorithms for solving differential equations.

References

Template:Reflist

Template:Math-stub

  1. Photograph, illustration, and description of the root(2) tablet from the Yale Babylonian Collection
  2. The New Zealand Qualification authority specifically mentions this skill in document 13004 version 2, dated 17 October 2003 titled CARPENTRY THEORY: Demonstrate knowledge of setting out a building