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In Excel, if I let the x value of {x, y} Cartesian coordinate pairs of a graph equal the cosine of rows 0 to 360, and then I let the y values equal the sines of rows 0 to 360 -- I have just taken all those row numbers and treated them as angles, right? So the result is a circle.
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In the Garthwaite Curve -- that ring of spiral balls you see me use all the time in many various ways -- I found out how to get 3-dimensionality out of Excel, by combining the z-dimension formula in with x and y (or in some other curves, just with y).
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The formula for the "ball", formally called a "spherical helix", is short but a little difficult to explain, so I won't. Suffice it to say that it multiplies the sine by the cosine and again by a cosine, or the sine by the sine and then by the cosine, of various values -- be they constants or variables. Now the sine of an angle, given r=the hypotenuse, is y/r, and the cosine of an angle is x/r. If we let r=1, then sine = just the distance up the y axis and the cosine = just the distance along the horizontal x axis.
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Imagine a triangle made by extending the hypotenuse at 30 degrees, then 45 degrees, then 60 degrees. At first, x is longer than y is tall. Then, at 45 degrees, both are equal. Then at 60 degrees, the roles are the exact reverse of what they were at 30 degrees and y is now taller than x is short by exactly the amount that x was longer than y at 30 degrees. So, therefore, in a circle, if the sine is long, the cosine is short and vice versa, or they're even. It's also possible that they measure 1 or 0, but those are the maximum and minimum values for a unit circle of radius r = the hypotenuse = 1.
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And, for other curves, we are usually distorting the sine and/or cosine by adding/multiplying/subtracting or dividing it by something else.
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Just when you think you understand, and you say to yourself, "Aha! Then the sine times the cosine produces a rectangle, the diagonal of which is the radius! I get it! I'm a genius!" ... it's not quite that simple, and yet it is also exactly that simple at the same time. It's just that the sine times the cosine do not define the endpoint of that diagonal when multiplied together, any more than 4*6 = 24 says anything about the point {4, 6} at the corner of the rectangle. Seems unfair, I know! I can sympathize, believe me. But you are a genius perhaps if you can agree that their multiplication as their values change produces the sequence (0, .25, .50, .25, 0, -.25, -.50, -.25, 0, .25, .50, .25, 0, -.25, -.50. -.25, 0)!!!
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Why? Because at 45 degrees, the sine and cosine = 1/2 the square root of .5, or .7071, and so there are 4 occurrences of .50 (2 positive and 2 negative), because there are 4 places on the circle where the sine and cosine are equidistant from the x and y axes. The .25's occur at each 15 degrees and there are 8 of those, two on either side of a .50. Then, there are 5 zeros: at 0 degrees, 90 degrees, 180, 270 and 360 degrees. Of course there are a lot of other values in between the 0 and the .25 and the .50, etc, etc., but that is the main way to understand it. This is then a "half-curve", relatively speaking.
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So if the sine and cosine vary between 0 and 1 ordinarily (without further adjustment), and they are ADDED together as one is small and the other is large, they will tend to equal 1. But if they are MULTIPLIED, they will equal at most .50 and at least, -.50
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How to Compare Two Methods of Creating a Spherical Helix Picture 14 If you can grasp that much, you are ahead of the game in terms of grasping trig and its ability to produce beautiful and unique designs that possess a unique clarity of definition, because when the "half-curve" is applied to a variable of 10pi to 0, the result is 5pi turns of the spiral of the helix of the sphere from one endpoint of 0 to the other endpoint of 0, which is a nice aesthetic number of turns to behold as a minimum.