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||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||

Online Volumes (Book Orders)
1,  Elements of Reason.
1A. Pattern Based Reason 
1B. Math Curriculum Notes
2. Three Skills for Algebra
   Three Skills for Algebra
3. Why Slopes & More Math
 Avid Readers: Try Pattern Based Reason  & chs 
 1 to 12, 14,  16 & 17  in  Three Skills for Algebra.
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1. Help Your Child/ Teen Learn 
2. Solving Linear Equations  
3. Fractions Ratios Rates Proportions, Units
4. Euclidean Geometry
5. Analytic Geometry/Functions 
6. Number Theory
7. Calculus Introduction
8. Complex Numbers 
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17. Math Education Essays
Teacher-Tutor Info & How-TOs
1. Arithmetic Reference
2. Algebra Starters 
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4. Geometry Starters
5. More Geometry
6. Calculus Modifiers 
7. Multiple Logics in Maths
8. Math Ed. Issues

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YOU are better than YOU think. Show yourself  how:  

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Read  logic chapters 1 to 5  in online volume Three Skills for Algebra  for greater skills & confidence in  work 
and study

Learn to read notes and textbooks like a lawyer, so that no nuance, no subtlety and no clause escapes your attention.

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 Logic chapters 1 to 5  re- appear not in sequence, as is or longer,  in  Volume 1A,  Pattern Based Reason, Bon Appetite.

Logic Mastery
 Amazing, Amusing, Amorous,  Delicious, Delightful, Edifying, Strengthening Elixir. 
It eases work & learning difficulties Makes the hard easier. Opens eyes. Leads to greater precision.
in reading and
writing

Logic mastery makes the hard, easier. Logic mastery  leads to better, stronger and richer comprehension.  Logic mastery  improves reading and writing.  Logic mastery ease learning difficulties.  Logic mastery gives a headstart.  In sum, logic mastery  will develops critical thinking, improve reading and writing, and give a firmer base for work and studies at many levels. Good luck.


After logic  (a) continue reading Three Skills for Algebra, chapters 8 to 14  and do so alongside site area on solving liinear Equations ; or (b) see this calculus starter lesson and Volume 3, Why Slopes  & More Math, chapters 2 to 6;

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Caution: Site advice is approximately correct, for some circumstances, not all. That leaves room for thought

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What may be learnt and when depends on how skills and concepts are developed. Making the hard easier and clearer will allow earlier & richer development of skills and concepts.


Try the Twiddla Whiteboard. In principle, it  allows to people to draw and chat together online on a copy of this webpage or a clean sheet. The chat may be via text or audio.  Visit www.twiddla.com to set up whiteboards to work with the webpage of your choice.

For online automated help in senior high school maths & calculus, visit  quickmath.com  For Automatic Calculus and Algebra Help with derivatives, integrals, graphs, linear equations, matrix algebra, visit calc101.com  With  overlap, each site quickmath & calc101offers a different range of services, some free, some not, all based on webmathematica. Good luck.

 

Parameters in Limits

If k is a real number which is constant or does not depend on x, then  

limx® a k f(x)  = k limx® a  f(x

For example,

limx® 3 k x2  = k limx® 3  x2  =  k 32 = k9 = 9k

when k = 1, 10, 55 or any number you choose.

If a number denoted by a letter k or q or p appears in a limit involving another (dummy) variable,  we call the number and the letter that denotes it, a parameter.  

To learn more about describing and talking about numbers and quantities.  read the long  essay [What is a Variable] and read  Volume 2, Three Skills For Algebra (chapters 8 & 9 )

A parameter a or x will occur in the forthcoming limit-based introduction of derivatives. 

  1. lim x® A a x2 +bx+c  = a A2 +bA+c  

    Here a, b, c and A are parameters. The right hand side depends on the parameters a, b and c, and A. When a =3, b = 4, c =10 and A = 2. The foregoing equation or template becomes

    lim x® 2 3 x2 +4x+10  = 3*22 +4*2+10 = 12 + 8 + 10 = 30
  2. Let  f(x) =  x2.  Then with the parameter a = 4 (or another value)

    f(a+h) - f(a) = (a+h)2-a =  a2  + 2h + h2   = 2ha + h2 =h(2a + h)

    Therefore
    lim
    h® 0 
    f(a+h)-f(a)
            h
     =   lim
    h® 0 

     h(2a + h)
     h

     = 

    lim
    h® 0 
    2a + h
    = 2a
    Re-read the foregoing with a =3, 8, 99, r (another parameter) or x. What changes?
  3. Let  f(x) =  x2.  Now rewrite the foregoing with an x instead of a. 

    f(x+h) - f(x) = (x+h)2-x =  x2  + 2h + h2   = 2hx + h2 =h(2x + h)

    Therefore

    lim
    h® 0 
    f(x+h)-f(x)
            h
     =   lim
    h® 0 

     h(2x + h)
     h

     = 

    lim
    h® 0
    2x + h
    = 2x

In examples 2  above, the limit process 

lim
h® 0 

applied to the a and h dependent expression

f(a+h)-f(a)
        h

eliminates the h dependence and results in an a-dependent expression 2a. Likewise in example 3, with x in place of the number a in example 2, the evaluation of the limit

lim
h® 0 
f(x+h)-f(x)
        h

results in an expression 2x which depends only on x and not on the eliminated or dummy variable h.  In the limit evaluations above, the variables x and a are parameters, and values of the limits are parameter dependent. 

In the discussion of derivatives for curves or functions y = f(x)  in the next or one of the next lessons, the evaluation of  

    lim
    h® 0 
    f(x+h)-f(x)
            h
gives an x-dependent result, 
    g(x) =  lim
    h® 0 
    f(x+h)-f(x)
            h

The formula for g(x) also written as f '(x) can be obtained from the formula for f(x) via a limit-based calculation or via calculation rules, obtained from the properties of limits, which go directly from the formula for f(x) to the formula for g(x) without an explicit evaluation of limits. 


 

 

 

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More Calculus
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Calculus Videos
0.   First Calculus Preview
0. Triangle Inequality
0 Inequalities
0. Solving Inequalities
1. Distance+Midpt Formulas
1. Function Domains
1.Polynomial Domain+Range
1. Fn:  Linear Combinations
1. Fn Composition II
1. Fn Composition I
1. Solving y**n = x**m
2 .Real Numbers
2. Limits Numerical View
2. Limits,. Formal Definition
2. Limit Properties Numerically
2. Decimal View of Limits
2. Error Control View
2. Limits & Continuity
2. Limit Vals via Substitution
2. Limits & Composite Fns
2.. Limit Examples
2. One Sided Limits
2. Infinity and Limits
2. Parameters in Limits
3. Derivative Motivation
3.  Derivative Definition I
3. Derivatives Definition II
3. Calculus: Why Radians
3 d/dx of sin(x) & cos(x)  (I)
3 d/dx of sin(x) & cos(x) (II)
3.Sum Rule
3. Product Rule
3. Power Rule
3. Previous Rules Combined
3. d/dx for Polynomials
3. Reciprocal Rule
3. Reciprocal Law: sec & csc
3. Reciprocals & Power Rule
3. Power Law for Integers < 0
3. Quotient Rule
3. Quotient Rule Examples
3. Quotient Rule: tan & cot
3.  Linear Chain Rule
3. Chain Rule for Powers
3. Chain Rule - Polynomials
3. Chain Rule Examples I
3. Chain Rule Examples II
3. Linear Approximation I
3. General Chain Rule
3. Inverse Fns Derivatives
3. Chain Rule: ln(x) & exp(x)
3. Square & Cube Roots
4.  Linear Approximation
4. Second Derivative Test
4. Sketch y = x^3 - 6x^2- 12x
4. Sketch y = x^3 - 3 x^2 - 9x
4. Sketch y = 1 - 1/(1+x^2)
5. Indefinite Integrals A
5. Indefinite Integrals B.
5  Indefinite Integrals C
6. Definite Integral D
6. Area Under Curves
7. Volume of a Sphere

To Learn More, visit Volumes 2 and 3.


Advanced Topics

Limit Properties Algebraically
Pigeon Hole Principle
Bolzano
Constant Difference Thm
Continuous Functions
Rational Functions
Mean Value Theorem
One Side Range Theorem
Range On One Side
From Lipschitz Continuity

To Learn More: Visit Real Analysis.

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