Solution 4.2:3b
From Förberedande kurs i matematik 1
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- | The angle | + | The angle <math>2\pi</math> corresponds to a whole revolution and therefore we see that if we draw in a line with angle <math>2\pi</math> relative to the positive ''x''-axis, we will get the positive ''x''-axis. |
- | <math> | + | |
- | corresponds to a whole revolution and therefore we see that if we draw in a line with angle | + | |
- | <math> | + | |
- | relative to the positive | + | |
- | + | ||
- | -axis, we will get the positive | + | |
- | + | ||
- | -axis. | + | |
[[Image:4_2_3_b.gif|center]] | [[Image:4_2_3_b.gif|center]] | ||
- | Because | + | Because <math>\cos 2\pi</math> is the ''x''-coordinate for the point of intersection between the line with angle <math>2\pi</math> and the unit circle, we can see directly that <math>\cos 2\pi = 1\,</math>. |
- | <math>\cos | + | |
- | is the | + | |
- | + | ||
- | -coordinate for the point of intersection between the line with angle | + | |
- | <math> | + | |
- | and the unit circle, we can see directly that | + | |
- | <math>\cos | + |
Current revision
The angle \displaystyle 2\pi corresponds to a whole revolution and therefore we see that if we draw in a line with angle \displaystyle 2\pi relative to the positive x-axis, we will get the positive x-axis.
Because \displaystyle \cos 2\pi is the x-coordinate for the point of intersection between the line with angle \displaystyle 2\pi and the unit circle, we can see directly that \displaystyle \cos 2\pi = 1\,.