Solution 4.2:3b

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m (Lösning 4.2:3b moved to Solution 4.2:3b: Robot: moved page)
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The angle
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<center> [[Image:4_2_3b.gif]] </center>
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<math>\text{2}\pi </math>
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corresponds to a whole revolution and therefore we see that if we draw in a line with angle
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<math>\text{2}\pi </math>
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relative to the positive
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<math>x</math>
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-axis, we will get the positive
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<math>x</math>
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-axis.
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[[Image:4_2_3_b.gif|center]]
[[Image:4_2_3_b.gif|center]]
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Because
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<math>\cos \text{2}\pi </math>
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is the
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<math>x</math>
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-coordinate for the point of intersection between the line with angle
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<math>\text{2}\pi </math>
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and the unit circle, we can see directly that
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<math>\cos \text{2}\pi =1</math>.

Revision as of 11:51, 28 September 2008

The angle \displaystyle \text{2}\pi corresponds to a whole revolution and therefore we see that if we draw in a line with angle \displaystyle \text{2}\pi relative to the positive \displaystyle x -axis, we will get the positive \displaystyle x -axis.

Because \displaystyle \cos \text{2}\pi is the \displaystyle x -coordinate for the point of intersection between the line with angle \displaystyle \text{2}\pi and the unit circle, we can see directly that \displaystyle \cos \text{2}\pi =1.