Lösung 4.3:2b
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
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- | If we write the angle | + | If we write the angle <math>\frac{7\pi }{5}</math> as |
- | <math>\frac{7\pi }{5}</math> | + | |
- | as | + | |
+ | {{Displayed math||<math>\frac{7\pi}{5} = \frac{5\pi+2\pi}{5} = \pi + \frac{2\pi }{5}</math>}} | ||
- | <math> | + | we see that <math>7\pi/5</math> is an angle in the third quadrant. |
+ | [[Image:4_3_2_b.gif||center]] | ||
- | + | The angle between <math>0</math> and <math>\pi</math> which has the same ''x''-coordinate as the angle <math>7\pi/5</math>, and hence the same cosine value, is the reflection of the angle <math>7\pi/5</math> in the ''x''-axis, i.e. | |
- | <math>\ | + | |
- | is | + | |
- | + | {{Displayed math||<math>v = \pi -\frac{2\pi}{5} = \frac{3\pi}{5}\,\textrm{.}</math>}} | |
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- | <math>v=\pi -\frac{2\pi }{5}=\frac{3\pi }{5}</math> | + |
Version vom 13:14, 9. Okt. 2008
If we write the angle \displaystyle \frac{7\pi }{5} as
we see that \displaystyle 7\pi/5 is an angle in the third quadrant.
The angle between \displaystyle 0 and \displaystyle \pi which has the same x-coordinate as the angle \displaystyle 7\pi/5, and hence the same cosine value, is the reflection of the angle \displaystyle 7\pi/5 in the x-axis, i.e.