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# Unit Circle

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By definition, (cos theta, sin theta) is the image point of (1,0) under a turn of magnitude, theta. Well, how do you graph a point of cos theta (or sin theta) when you''re only given that one part of the point? Do you assume that when you are told to graph cos x, that you plot (cos x, sin x)?
Charles Hwang -aka oatmeal.net [Maxedge My Site(UC)|E-mail|NeXe|NeHe|SDL] [Google|Dev-C++|GDArticles|C++.com|MSDN]

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I think this question is a little vague. Sinx = 1 - cos^2(x) so you could graph both, but it depends HOW they want you to graph cosx. So how do thye want you to graph it? Cartesian? Polar? Please expound.

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Yeah, it''s a little vague. Graph a "point" of cos(x)? What people usually mean by "graph cos(x)" is to let y = cos(x), make some sort of list of numbers (let x be measured in degrees):

x | y
0 | 1
30 | 0,866
45 | 0,707
60 | 0,5
90 | 0

(You get the idea), and then marking those points in a graph. Not totally unlike graphing, say, y = 3x + 5.

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It says: A trigonometric value is given. Draw the corresponding point on the unit circle.

Charles Hwang -aka oatmeal.net
[Maxedge My Site(UC)|E-mail|NeXe|NeHe|SDL]

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Sounds like homework, so I can''t answer according to the forum rules.

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Sinx = 1 - cos^2(x)

should be

Sin²(x) = 1 - cos²(x)

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That''s technically impossible unless you are given some indication of what quadrant the angle''s in. Anyways, the number''s probably given as a ratio. Ignoring the unit circle for now, draw in a right triangle with sides in the ratio given, use the pythagorean theorem to find the third side, and divide the necessary sides to find the answer.

This answer is intentionally vague to make you try and reason out what needs to be done. In the future please try to avoid posting homework questions.

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get a ti83 and graph sin(x). perhaps you have heard of a sine wave?

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