Appetizers and Lessons for Mathematics and Reason 
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19 Logs & Powers
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Why Slopes
and
More Math
Volume 3

Vol 2, Three Skills for Algebra covers many  topics in algebra and logic that students starting calculus should have mastered or will have to master. Also includes arithmetic review problems to catch common mistakes.  A fourth skill  gives a unifying theme for high school maths.
 Vol. 3, Why Slopes & More Maths, gives starter lessons for differential and integral calculus. In contrast, its hard appendices gives starter lessons for real analysis in the form of decimal-based  proofs of theorems normally stated without

Content Guide
Foreword
Chapter Descriptions
1. Introduction
Calculus Appetizer (1983)
2. Second Preview Begins
2 Skier in Motion (V)
2 The Skier (V)
2. Position Dependent (V)
3 Slope & Extrema (V)
4 Single Factor Analysis (V)
4 Two Factor (V)
4 More Factors (V)
4 With Divisors (V)
5 Maxima & Minima Tests
6 Jumps & Discontinuities
8 Review  (optional)
9 On Calculus Studies
11 Slope of Slope
13  Acceleration
14 Limits & Error Control (V)
14 Limit of a Fn.
14. Limited Error Control
14 Signif. Digits
14 Cauchy Limits
14 Sequence Limits
14 Decimal Arith.
15 What is Slope (V)
15 Slope Calculation (V)
15 Slope, a Limit
15 Tangent Lines
15 Linear Approx.,
15 Limits via Algebra (V)
15 Recap.
PS.Chain Rule for Polys
PS Chain Rule- General  (V) -
PS More Chain Rule (V)
PS - Sign Analysis (V)
16 What is Velocity
17  What is Area
18 Integration
18 Area Calculation
18  Fn DefN, 6 Ways
19 Logs & Powers
19 Natural Log.
19 Exponential Fn.
20 What's Next
21 Add Vectors
22 Complex #'s
23 Complex #'s
23 Trig Identity
23 Proofs of.
24 Complex Logs etc

Units in Calculations:
7 Velocity
7 Varying Velocity Example
7. Velocity Calculation
7 Changing Units
7 Same Velocity  Motions
10 Slopes without Units.
10 Units & Slopes
10  Units in Cost vs. Quantity
10  How Units  Appear
10 Unit  Elimination
10 Partial Elimination
10 Interest & Units
12 More on Units

Appendices:

Pigeon Hole Principle
Constant Difference Thm
Continuous Functions
Rational Functions
Mean Value Theorem
One Side Range Theorem
Range On One Side Theorem
Integration & Lipschitz
 Continuity


These appendices continue the
decimal viewpoint of limits, error
control and continuity begun
in Chapter 14. The One Sided
 Range Theorem
is a postscript,
not in printed version.

Chapter 19
Real Logs, Powers and Exponentials

Questions

What does an electronic calculator compute when the natural logarithm button on it is pressed? The answer follows from a long chain of mathematical concepts and reasoning. The definition below of the natural logarithm in terms of area under a curve y = [1/(s)] provides a preview (or review) of notions employed in integral calculus - the subject which treats, in the first instance, the calculation of areas under curves. This chapter assumes a previous acquaintance with logarithms, powers and exponentials.

Electronic Calculators

Electronic calculators allow the illustration and an electronic, pre-programmed confirmation of the basic relationships between logarithms, exponentials and powers. The following computations can be illustrated with an electronic calculator.

FOOTNOTE: This represents or indicates the easy buttons-on-a-calculator approach to the description/explanation of logarithms, exponentials and powers together with the relationships between the calculations invoked by the buttons.


  1. The logarithm of x > 0 to a base a > 0 is given by
    loga(x) = ln(x)
    ln(a)
    ·
    For example on some electronic calculators, log10(6) is giving by pressing the 6 and then the log button (in some order). This should give the same result as computing ln(6)¸ln(10). (Exercise: check this by pushing buttons.)
  2. Multiplying a number a > 0 by itself n times gives an. But the calculation of exp(n ln(a)) gives the same result. So the original definition of an for a > 0 is consistent with the more general definition given for real numbers x by
    ax = exp(x ln(a)).
    For examples, compute 52 and exp(2ln(5)) on an electronic calculator. Also compute the following:
    x
    = 100.2,     y = exp(0.2ln(10)),     
    x
    5 and exp(5 ln(x)).
  3. For a > 0,
    loga(ax) = x
    and for v > 0, u = loga(v) implies au = v. For examples compute log(103)-3 and 10log(8).
The special cases a = 10 and a = 2 are of interest most likely due to the recent historical preference for decimal (base 10) arithmetic and due to, still more recently, to the advent of computers with their binary (base 2) arithmetic. Also of interest is a third case a = e where e is the so-called natural number. See below.

Definitions of logarithms and exponential functions are given in the next two webpages to explain and derive the computational relationships described above.


Two site descriptions introduce further site content.   Bon Appetite.

  • Math Forum, 1996 online classification of the then  dozen or so math lesson giving  websites: ... There are appetizers for algebra, arithmetic, logic, better learning in general, reason, theorem proving and complex numbers.  Strengths here are in Alan's explanation of mathematical concepts using words and stories: ...     
  • Magellan, the McKinley Internet Directory, 1996: Mathphobics, this site may ease your fears of the subject, perhaps even help you enjoy it. The tone of the little lessons and "appetizers" on math and logic is unintimidating, sometimes funny and very clear. There are a number of different angles offered, and you do not need to follow any linear lesson plan. Just pick and peck. The site also offers some reflections on teaching, so that teachers can not only use the site as part of their lesson, but also learn from it.

 
Calculus Students:  Hire the site author, as an online tutor.  Invitations to group lessons on popular or much needed topics may follow.   Site Reviews may serve as references.  Online whiteboards with  voice and real-time writing make online tutoring easy and efficient - board content printable.  Text or written work scanned or saved to a  pdf file may be  uploaded  for discussion in the whiteboard.  The first lesson is free to show what is offered. Bon Appetite.

www.whyslopes.com

Parents: Help your Child/Teen Learn

Online Volumes
 
(orders)
1,  Elements of Reason. 1996
1A. Pattern Based Reason  1995
1B. Math Curriculum Notes 1996
2. Three Skills for Algebra  1995
3 .Why.Slopes.&
.More.Math.1995

Math How-TOs etc  2008
1. Arithmetic
2. Algebra 
3. More Algebra 
4. Geometry  
5. More Geometry
6. Calculus

Site Description/Reviews  by 3rd parties

Site  Math Lessons
1. Arithmetic Flash Videos  11-2008
2.  Algebra Videos (to appear)
3. Fractions and More 
4.. 
Solving Linear Equations  04-2005
5. Euclidean-Geometry To Complex No.s 
6.  Analytic Geometry/Functions 2006
7.  Number Theory. 2006-7
8.
  Exponents, Radicals & logs. 2008
9 Calculus  2005
10..Real  Analysis 1995
11 Electric Circuits Etc  2007
12. .Algebra, Odds & Ends, HS level-2001

For Math Instructors/Tutors/
Curriculum Committees


1. K0-11Applied Math Program Outline  
2. Mathematics education  essays 
3. LAMP - an earlier applied math program.
4.
Maps, Plans,  Similarity &Trig, with
Complex   Numbers
, 12-2009. 
(150 pages)

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