www.whyslopes.com 
Appetizers and Lessons for Mathematics and Reason  
for calculus, preparation for calculus & math ed. reform, etc

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

 Mathematics Course Designers: LAMP offers food for thought.
More Site Areas 
1. Help Your Child or Teen Learn 
2. Solving Linear Equations
3. Fractions Ratios Rates Proportions & Units
4. Euclidean Geometry
5. Analytic Geometry/Functions 
6. Number Theory
7. More Calculus
More Site Areas 
8. Complex Numbers 
9. Qc Maths  Education  
10. Secondary IV(?) maths
11. Real  Analysis 
12. LaTeX2HotEqn:
13. Electric Circuits Etc  
14.  Français
15. Algebra, Odds & Ends, Etc
More Site Areas 
16. Math Education Essays
17. Telling & Working with Time
18. Maps, Plans & Drawings
19. Quantitative Skills for  home, shopping and work 
20. Statistics Useful, or Not.

Test the
Twiddla Whiteboard

 ||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||
Back ] Advice & Directions ] Next ]


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.


Side-Side-Side Triangle Method for
Triangle Construction and Duplication

Given the length of three side of a triangle ABC, we can construct an isometric triangles DEF and DFH with the use of a straight lines, or ruler and compass. The construction method is described in greater detail below. Click on image

SSS method  
Given the length of 3 sides of an existing triangle, we can use ruler and compass (or strings) to construct an  isometric copy or two. 

Method.

Step 1.  Draw a base DF equal in length to the larges side AC of the original triangle. 

Step 2.  Draw circles with radii given by the lengths of the other two sides in triangle ABC, centred at end-points D and F of line segment DF.

Step 3.  use the intersection points of the circles, here labeled E and F to provide a third vertex of two triangles with side EF.

Then the two resulting triangles are isometric to the original triangle 

Empirical Remark 1: Drawings with the larger radius circle centered at D instead of F would result in two more triangles isometric to triangle ABC. Thus for any line segment DF, there are upto four instances of the SSS triangle construction method.

Empirical Remark 2:  The foregoing construction method can be applied starting with side AC of the triangle ABC. That construction method with it four variations would result in 4 triangles isometric to ABC.   The first would be coincident with ABC. A second would have a vertex B' on the same side of AC as B.  A third would have a vertex D given by the reflection of B across side AC, or the line through it. The fourth would have a vertex D' equal to the reflection of B' across side AC or the line through it.  The triangle AD'C would be given by a 180 degree rotation of the triangle ABC about the center of side AC. 

 SSS Isometry Assumption

If there is a correspondence between the vertices such that corresponding sides are have equal lengths then the triangles are isometric. Moreover,  both could be built or rebuilt by the same construction SSS method, and each may be moved by a sequence of  translations, rotations and/or reflections, so that sides and vertices coincide with the other.
 

A side-side-side like Construction - Location of a point.

Scenario 1:  A point P is to be placed 20 meters away from a point A and 25 meters away from a point B, and north of both points.   Two surveyors attach a string (or tape measures) of length 20 meters at A and another of length 25 meters at B. Holding the strings taught they move the other ends of the string until the ends meet. That locates the point P. 

Scenario 2.  Two surveyors observe a point P is 20 meters away from a point A, and 25 meters away from a point B, and further north than both.  On a map drawn to a scale of 1 cm to 10 meter, they locate P on the map by finding the Northern most intersection of a circle of radius 2.0 cm centered at the map location of A with another circle of radius 2.5 cm centered at the map location of B. That yields the coordinates of P on the map and actual.

Uniqueness Observation and Assumption: If one side AB of a triangle ABC is given then the Side Side Side construction method applied to end points of the line segment AC leads to two isometric triangles, the original triangle ABC and a second triangle ADC - isometric by the assumption above.

The discussion of this situation will be continued below.

 

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4. Euclidean Geometry

Advice & Directions
Correspondence
Isometry
Side-Side-Side
Side Angle Side
Angle-Side-Angle
Isoceles
Right Bisector Construction, Etc.
Perpendicular - Point to Line
SSS Failure
SAS Failure
ASA Failure
Parallel Lines
Angle Sum
Similarity
Right Triangle Similarity
Trig  or Similarity
Parallelograms
Kites From Triangles Duplication
Parallelogram from Triangle Duplication
Addition of points in the plane
Multiplication of Points in the Plane
Distributive Law, Step I
Distributive Law, Step II
Distributive Law, Step III


Above Average Students in Geometry may enjoy  the site geometric introduction of complex numbers and the wordy volume 1A,  Pattern Based Reason.

For algebra, logic starter lessons,  see Volume 2, chapters 1 to 12, plus 14, 16 and 17.

Analytic Geometry, Functions & Trig

(FN) What are Functions?
(FN) Functions - More
SZM: Sign, Zero, Monoticity
(L) Lines Summary
(P) Polynomials (*,+,-)
(Q) Quadratics
(D) Simplify Square Roots
(T) Unit Circle Trig
Conic Sections


More For Analytic Geometry:

Real Numbers
Say More Positive
Linear Inequalities
Triangle Inequality
Absolute Value |x|
|x| Eq'ns & Inequalities
Rectangular Coords
Shortest Path
Distance Formulas
Add & Multiply Points
Polar Coordinates
Radians
(A) Vectors
(A) Coordinate Arithmetic
(A) Navigation on Maps
(A) Addition Geometrically
(A) Rotation
(PT) Translations
(PT) Dilatations
PT: Rotations

Easy Consequences of  this (newest) Complex Number. Starter Lesson follow below to provide an alternate development of HS or college maths.

Vec & Cmplx  No Applet
B2 C. Conjugates
B3 Pythagoras
B4 Distance
B5 Rt Triangle Similarity
B6 Trig., Functions
B7 Dot & Cross Products
B8 Cosine Law
B9 Exponential & cis fns
B10 Easy Trig Identities
B11 Set Viewpoint

Lesson Plans and lessons

Secondary I - fractions & allied concepts (decimals, percentages)

Secondary II - Algebra  (arithmetic versus algebraic methods, backward use of formulas and proportionality equations)

Secondary IV - Functions to Trig & Statistics

Calculus Intro 

Algebra Lesson Notes - All levels

Great_Expectations: If you can learn to follow a multi-step methods in any subject precisely, you can do so in other subjects, as well.

Good news: Site pages  identify what you need to study.

Bad news: Site pages do not explain everything  

Worse news: Learning takes time, yours

 


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a 1983 McGill. Ph. D. in mathematics
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