MAT129 Fall 2025 Notes
mathnstuff.com/math/precalc/MAT129fa25/p.9.htm
© 2025   A2, Agnes Azzolino
(Polynomial)/(polynomial) = (rational fx)
Rational Functions, Asymptotes and Graphing. Text 5.6, PG. 414

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(Polynomial)/(polynomial) = (rational fx)
Hi,
    When one divides polynomials, rational (as in ratio or fraction) functions are created.
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5.6  - Rational Functions: Asymptotes and Graphing, pg. 414
	* Use arrow notation.
	* Solve applied problems involving rational functions.
	* Find the domains of rational functions.
	* Identify vertical asymptotes.
	* Identify horizontal asymptotes.
	* Graph rational functions.
Rational Function Definition & Notation
Precalc definition:
an algebraic expression or function, produced by the DIVISION of polynomials, with the use of one variable x -- fraction expressions or fraction functions
 
anxn + an-1xn-1 + an-2xn-2 + ... +a2x2 + a1x1 + a0x0
__________________________________________
bnxn + bn-1xn-1 + bn-2xn-2 + ... +b2x2 + b1x1 + b0x0
 
in which the constants an, an-1, an-2, ... , a2, a1, a0, bn, bn-1, bn-2, ... , b2, b1, b0 are real,
and serve as coefficients or the constant term,
and in which all exponent of x are counting numbers.
Rational Functions
  • To provide a list of things to do when sketching a rational function,
  • To provide two examples of sketching rational functions,
  • To give you a problems to try and their solution, and
  • Features of a Rational Function
  • Sketch f(x) = [ (x2 - 4)(x + 3)] / [(x+2)(x-1)] animation
  • Synthetic division & long division notes
          to find zeros
          to rewrite a rational function to find horizontal and other asymptotes and
          to determine the end behavior.
  • ratl.xls
    • Graph and table of (Axm)/(Bxn)
      Watch the power of the top or bottom equal or dominate the other.
      Examine hoirzontal asymptotes or infinite increase or decrease.
      Think endbehavior and explore.
    • Graph and table of rational function, polynomial A(x) divided by B(x).
      Examine asymptotes.
      Examine the role of factors A(x) and 1/B(x).
    • Graph and table of rational functions written as A(x) / B(x) + C(x)
      Really play with C(x), the asymptote
    • Complete synthetic division and rewrite of quotient and remainder.
  • recipfx.gsp   -- graph of parameter-defined reciprocal function,
        * with slide-able tangent line,
        * VERTICAL ASYMPTOTE MUST BE POSITIONED BY USER!
  • asymptote definition
  • end behavior   -- definition increasing/decreasing
  • Who Has? Rat'l F(x) Game
COMPOSITION -- Composition of Functions
polynomial, rational functions pdf
compositeFX.gsp  -- build 2 functions using other functions
compositeFx.poly.ratl.gsp   -- build functions using other functions
0 - graph of 1 function
1 - graphs of 2 functions
2 - composite of 4 functions
3 - polynomial. links to polynomial, dilations gif, quatratic.htm, equation, discriminant
4 - rational, rational function features & how to find them
5 - end behavior, battle of (Ax^m)/(Bx^n)
spread sheet notes
Spread Sheets -- Dynamic Computation
  • polynomial spreadsheet --
        graph a polynomial function written in factored form
        complete synthetic division
  • synthetic division spreadsheet -- just complete synthetic division of a polynomial or of a quadratic by a linear binomial
  • rational function spread sheet
        Graph and table of (Axm)/(Bxn)
        Watch the power of the top or bottom equal or dominate the other.
        Examine hoirzontal asymptotes or infinite increase or decrease.
        Think endbehavior and explore.
        Graph and table of rational function, polynomial A(x) divided by B(x).
        Examine asymptotes.
        Examine the role of factors A(x) and 1/B(x).
        Graph and table of rational functions written as A(x) / B(x) + C(x)
        Really play with C(x), the asymptote
        Complete synthetic division and rewrite of quotient and remainder.