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


Generating functions in combinatorics.
== 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.

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.