# Macro Library polys

Polynomial functions. Version 1.1, Nov 11, 2007

- formpoly
- formpolyfromroots
- writepoly
- addpolys
- subtpolys
- multpolys
- scalepoly
- derivepoly
- polypower
- quadroot
- getcoef

### formpoly

formpoly(coefficients,powers or degree)
Creates a polynomial object
Use writepoly to create a display form of the polynomial
coefficients: list/array of coefficients
powers or degree: list/array of powers, or highest degree
highest degree assumes coefficients correspond to consecutively
decreasing powers

### formpolyfromroots

formpolyfromroots(stretch,roots,[multiplicities])
create a polynomial object from roots
use writepoly to create a display form of the polynomial
stretch: a stretch factor; the A in A*(x-root)(x-root)...
roots: an array of the roots (zeros, x-intercepts) of the polynomial. For a complex root pair a+-bi give a single array [a,b] as the root.
multiplicites (optional): an array of multiplicites of the roots. Assumed to
be all 1 if not provided

### writepoly

writepoly(poly,[var,showzeros])
Creates a display form for polynomial object
poly: polynomial object, created with formpoly
var: input variable. Defaults to x
showzeros: optional, defaults to false. If true, shows zero coefficients

### addpolys

addpolys(poly1,poly2)
Adds polynomials, arranging terms from highest to lowest powers

### subtpolys

subtpolys(poly1,poly2)
Subtracts polynomials: poly1-poly2, arranging terms from highest to lowest powers

### multpolys

multpolys(poly1,poly2)
Multiplies polynomials

### scalepoly

scalepoly(poly,c)
Multiplies each term of poly by constant c

### derivepoly

derivepoly(poly)
Computes the derivative of poly

### polypower

polypower(poly,power)
Calculates poly^power

### quadroot

quadroot(a,b,c)
Quadratic equation, solving ax^2+bx+c = 0
Return an array of the two solutions, ordered smaller then larger
if no solution exists, an array of "DNE" strings is returned

### getcoef

getcoef(poly,degree)
Gets the coefficient corresponding to the degree specified
if no such term is defined, 0 is returned (since that is the coefficient!)
poly: polynomial object, created with formpoly
degree: degree of term to get coefficient of