Lösung 4.4:1b
Aus Online Mathematik Brückenkurs 1
(Unterschied zwischen Versionen)
K (Lösning 4.4:1b moved to Solution 4.4:1b: Robot: moved page) |
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- | {{ | + | The easiest angle to find is |
- | < | + | <math>v={\pi }/{3}\;</math> |
- | {{ | + | in the first quadrant. When we draw the unit circle, we see that the angle which makes the same angle with the positive |
+ | <math>x</math> | ||
+ | -axis as | ||
+ | <math>v={\pi }/{3}\;</math>, but is under the | ||
+ | <math>x</math> | ||
+ | -axis, also has a cosine value of | ||
+ | <math>{1}/{2}\;</math> | ||
+ | (same | ||
+ | <math>x</math> | ||
+ | -coordinate). | ||
+ | |||
[[Image:4_4_1_b.gif|center]] | [[Image:4_4_1_b.gif|center]] | ||
+ | |||
+ | There are thus two angles, | ||
+ | <math>v={\pi }/{3}\;</math> | ||
+ | and | ||
+ | <math>v=2\pi -{\pi }/{3}\;={5\pi }/{3}\;</math> | ||
+ | which have their cosine value equal to | ||
+ | <math>\frac{1}{2}</math>. |
Version vom 12:31, 30. Sep. 2008
The easiest angle to find is \displaystyle v={\pi }/{3}\; in the first quadrant. When we draw the unit circle, we see that the angle which makes the same angle with the positive \displaystyle x -axis as \displaystyle v={\pi }/{3}\;, but is under the \displaystyle x -axis, also has a cosine value of \displaystyle {1}/{2}\; (same \displaystyle x -coordinate).
There are thus two angles, \displaystyle v={\pi }/{3}\; and \displaystyle v=2\pi -{\pi }/{3}\;={5\pi }/{3}\; which have their cosine value equal to \displaystyle \frac{1}{2}.