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tutorfinder.com.au
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findatutor.ca
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Montreal Tutors
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use or become a tutor at your own risk
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.
| |
Trig Identities Simplified
The verification or derivation of trig identities can be reduced to algebraic
manipulations involving the cis(q) function
| cis(q) =
cos(q) + i sin(q)
= exp(i q) |
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and the property
| exp(ia)
exp(ib) = exp(i(a+b)) |
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The latter property, as said, follows from the polar coordinate, add the
angle, multiply the lengths rule for multiplication of complex
numbers.
The demonstration of many trig identities without the use of the properties
of the function cis(iq) is an enormous task,
or a delicate procedure, a needless but traditional exercise in some
trigonometric courses.
BabyTalk: Trig students meet the cis function (cosine i sine
function) when teachers or course design prefer not to speak about
exponentials exp(i q) of imaginary or
complex numbers.
Angle Sum Formulas, Two Proofs
Two proofs of the angle sum formulas are given next. The first recalls the
rotate-a-triangle proof met in trigonometry. The second derives the formulas in
three steps from the add the angles, multiple the lengths definition of
complex multiplication. Both proofs rely on the addition of angles and rotation
of points on the unit circle. The rest of this section is optional reading
especially if you have seen proofs of these angle sum formulas.
First Proof
This proof of the angle sum formula for sines and cosines involves the
rotation about the origin by the angle b of a
triangle formed by the vertices (0,0), (1,0) and (cos(a-b),sin(a-b))
into the triangle with vertices (0,0), (cos(b),sin(b))
and (cos(a),sin(a))
respectively. We assume this rotation does not change the lengths of the sides
of the triangle - that it is, a rigid body motion.

The original triangle and the rotated triangle both have a side that is a
chord on the unit circle. The length of this side is not changed by the
rotation, at least that is our geometric assumption. Therefore computation of
chords length squared can be done with the help of its end-point coordinates
before and after rotation. And the two computations should give the same result.
This implies
cos(a-b)-1)2+(sin(a-b)-0)2
= (cos(a)-cos(b))2+(sin(a)-sin(b))2
The latter in turn implies
| 1-2cos(a-b)+(cos(a-b))2+(sin(a-b))2 |
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| (cos(a))2-2cos(a)cos(b)+(cos(b))2 |
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| +(sin(a))2-2sin(a)sin(b)+(sin(b))2 |
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Therefore
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| 2-2cos(a)cos(b)
-2sin(a)sin(b) |
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From this,
| cos(a-b)
= cos(a)cos(b)
+sin(a)sin(b) |
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The replacement of b by -g
yields
| cos(a+g)
= cos(a)cos(g)-sin(a)sin(g) |
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as sin(-g) = -sin(g).
The identity cos(q) = sin(90°-q)
implies the identity cos(90°-q)
= sin(q). Together, the identities imply
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| cos(90°-a)cos(-g)-
sin(90°-a)sin(-g) |
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| sin(a)cos(-g)-
cosa)(-sin(g)) |
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| sin(a)cos(g)+
cosa)(sin(g)) |
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as cos(-q) = cos(q). This
completes the rotate-a-triangle proof for the angle-sum formulas.
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www.whyslopes.com
Volume 3, Why Slopes and More Math -
Foreword, One Calculus preview and Online Chapters:
(V) signals video (RealPlayer Format) to
watch
Area Entrance & Hub Foreword Chapter Descriptions 1. Introduction 2. Calculus Starter Lesson 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 Content Guide
Enriched material: The Appendices of Volume
3 are located in the Real
Analysis Area.
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.
Online Volume 2, Three Skills
for Algebra, Chapters 1 to 25 - skip 18., verbalizes and explains key
skills and concepts, those needed in calculus, again to make the hard easier.
A visual understanding of complex
numbers may help - serve as back ground info, in partial fraction
decomposition.
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