Using a Computer Algebra System (CAS),

{Use your favorite Computer Algebra System (CAS), like Maple, MatLab, etc. to evaluate the following functions at the given points:

  1. tex2html_wrap_inline60 , for x=-2, -1, 0, 1.23, 1.414, 2.7. What happens when x < 0? Conclude that the natural domain of f is tex2html_wrap_inline68 .
  2. tex2html_wrap_inline70 , for x=-4.37, -1.7, 0, 3.1415, 12.154, 16.2. Are there any values of x for which g(x) is not defined as a real number? Explain.
  3. tex2html_wrap_inline78 , for t=-2.1, 0, 1.2, -4.1, 9. Most CAS define power functions only when the base is positive, which is not the case if t<0. In this case the natural domain of f is tex2html_wrap_inline86 even though the CAS wants us to believe that it is tex2html_wrap_inline88 . So, be careful when reading off results using a CAS.
  4. tex2html_wrap_inline90 . Evaluate g(-1), g(0), g(0.125), g(1), g(1.001), g(20), g(1000). Determine the behavior of g near x=1. To do this use values of x just less than 1 and then values of x just larger than 1.
  5. Define a function f by

    displaymath58

    Evaluate tex2html_wrap_inline112 . Show that tex2html_wrap_inline114 for every value of tex2html_wrap_inline116 .

  6. Let tex2html_wrap_inline118 .

    a) Evaluate tex2html_wrap_inline120 .
    b) Explain your results.
    c) What is the natural domain of f?
  7. Evaluate the following inequalities graphically:

    For example, to solve the inequality |2x-1| < 3 use your CAS to
    a) Plot the graphs of y = |2x-1| and y=3 and superimpose them on one another
    b) Find their points of intersection, and
    c) Solve the inequality (see the figure below)


    The answer is: -1 < x< 2.

    a) |3x-2| < 5
    b) |2x-2| < 4.2
    c) |(1.2)x - 3| > 2.61
    d) |1.3 - (2.5)x| = 0.5
    e) |1.5 - (5.14)x| > 2.1

  8. Find an interval of x's such that
    a) tex2html_wrap_inline144
    b) tex2html_wrap_inline146
    c) tex2html_wrap_inline148

    Hint: Plot the functions on each side of the inequality separately, superimpose their graphs, estimate their points of intersection visually, and solve the inequality.

  9. Plot the values of

    displaymath150

    for small x's such as tex2html_wrap_inline154 etc. Guess what happens to the values of f(x) as x gets closer and closer to zero.

  10. Let tex2html_wrap_inline160 , for tex2html_wrap_inline162 . Use the Box method to evaluate the following terms, called the iterates of f:

    displaymath166

    where each term is the image of the preceding term under f. Are these values approaching any specific value? This is an example of a chaotic sequence and is part of an area of mathematics called ``Chaos".

  11. Sketch the graphs of tex2html_wrap_inline170 and compare these graphs with those of tex2html_wrap_inline172 .

    Use this graphical information to guess the general shape of graphs of the form tex2html_wrap_inline174 for p > 1 and for 0 < p< 1. Guess what happens if p < 0?
  12. Plot the graphs of the family of functions tex2html_wrap_inline182 for tex2html_wrap_inline184 .

    a) Estimate the value of those points in the interval tex2html_wrap_inline186 where f(x) = 0.
    b) How many are there in each case?


Angelo Mingarelli
Mon Sep 13 13:55:30 EDT 1999