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Tutors - All Subjects YOU are better than YOU think. Show yourself how:
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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 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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-/[]\- 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. |
Polar CoordinatesA quick review
Given a point A in a planar map with coordinates, we can measure its distance R from the origin and measure in a counterclockwise manner, the angle a it makes with the horizontal coordinate axis. Geometrically or physically we assume, the distance R and the angle a uniquely determine the point, and the vector from the origin to the point
The ordered pair (r units, a ) with round brackets provides the polar coordinates of a point A in the plane. Here r units is the length of the the associated "position" vector OA which goes from the origin O to the point A. This vector makes an angle alpha with the horizontal axis. Polar to Rectangular Coordinates, and BackWe will write [a,b] = (R,q) when both sides locate, determine or correspond to the same point in the plane. I assume you know how to measure the rectangular coordinates [a,b] and polar coordinates (R, q) of points in the plane, given the location. This provides a geometric mechanism for determining rectangular coordinates from polar coordinates, and vice-versa. (Methods based on trigonometry will be available later.) The point with polar coordinates (R,q) has length R and angle q. [Angles are determined for each point, modulo 360 degrees.] | b | * [a,b] =(R, q) | o | o | o | o | o \ angle q | o | --------o----------+----------------- | a | | Figure 1. Rectangular and Polar Coordinates of a Point. Each point [a,b] in the plane can be identified with the arrow, head at it, and tail at the origin. For the following topic, recall the discussion of arrow addition using horizontal and vertical coordinates.
round () versus square brackets []In the following lessons, if I remember, I will use round brackets () with polar coordinates. Your textbooks may use round brackets for both polar and rectangular coordinates. Matching pairs of round (), square brackets [] and braces {} will also be used in computations to indicate the order in which calculations are done. This could lead to bracket and parenthesis over use. |
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