Polynomial: Difference between revisions

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== Examples ==
== Examples ==
The [[Solid|volume]] of a cube is a polynomial in its side length.  
The [[Solid|volume]] of a cube is a polynomial in its side length.  
The signed area of an n-dimensional parallelogram spanned by vectors <math>v_1, \cdots, v_n</math> is a polynomial in the components of the vectors. In fact, it is the ''determinant'' of the matrix built out of those components.


Every [[linear transformation]] is uniquely associated to a polynomial called its characteristic polynomial.  
Every [[linear transformation]] is uniquely associated to a polynomial called its characteristic polynomial.  


A computer program consisting of some number of <code>for</code> loops (and no recursion or <code>goto</code>s or other loops), where each <code>for</code> loop runs exactly <math>n</math> times, will take a number of steps to run which is given by some polynomial in <math>n</math>. In fact, any polynomial at all can be realized in this way.
A computer program consisting of some number of <code>for</code> loops (and no recursion or <code>goto</code>s or other loops), where each <code>for</code> loop runs exactly <math>n</math> times, will take a number of steps to run which is given by some polynomial in <math>n</math>. In fact, any polynomial with <math>\mathbb{Z}_{\geq 0}</math> coefficients can be realized in this way.
 
Some generating functions in combinatorics or representation theory (those which truncate after a finite number of powers).
 
A truncated Taylor series approximation to anything. Tangent line to a curve at a point, tangent conic to a curve at a point, tangent cubic to a curve at a point, etc.  


Generating functions in combinatorics.
Piecewise polynomial functions (a type of ''spline'') are used in computer graphics to make things look smooth.


== Rational functions [TODO move to its own page] ==
== Rational functions [TODO move to its own page] ==
There are many examples of useful, practical rational functions that arise as ratios between square distances in trigonometry. See Norman Wildberger's book.
There are many examples of useful, practical rational functions that arise as ratios between square distances in trigonometry. See Norman Wildberger's book.

Latest revision as of 20:29, 18 November 2024

A polynomial is any function which obtains its result solely by some combination of: multiplying its inputs together, adding them together, or rescaling them.

Examples

The volume of a cube is a polynomial in its side length.

The signed area of an n-dimensional parallelogram spanned by vectors is a polynomial in the components of the vectors. In fact, it is the determinant of the matrix built out of those components.

Every linear transformation is uniquely associated to a polynomial called its characteristic polynomial.

A computer program consisting of some number of for loops (and no recursion or gotos or other loops), where each for loop runs exactly times, will take a number of steps to run which is given by some polynomial in . In fact, any polynomial with coefficients can be realized in this way.

Some generating functions in combinatorics or representation theory (those which truncate after a finite number of powers).

A truncated Taylor series approximation to anything. Tangent line to a curve at a point, tangent conic to a curve at a point, tangent cubic to a curve at a point, etc.

Piecewise polynomial functions (a type of spline) are used in computer graphics to make things look smooth.

Rational functions [TODO move to its own page]

There are many examples of useful, practical rational functions that arise as ratios between square distances in trigonometry. See Norman Wildberger's book.