Processing Math: Done
Solution 4.2:3d
From Förberedande kurs i matematik 1
(Difference between revisions)
m |
|||
Line 1: | Line 1: | ||
- | In order to get an angle between | + | In order to get an angle between <math>0</math> and <math>\text{2}\pi</math>, we subtract <math>2\pi</math> from <math>{7\pi }/{2}\,</math>, which also leaves the cosine value unchanged |
- | <math>0</math> | + | |
- | and | + | |
- | <math>\text{2}\pi </math>, we subtract | + | |
- | <math> | + | |
- | from | + | |
- | <math>{7\pi }/{2}\ | + | |
- | , which also leaves the cosine value unchanged | + | |
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
- | + | ||
+ | {{Displayed math||<math>\cos\frac{7\pi}{2} = \cos\Bigl(\frac{7\pi}{2}-2\pi\Bigr) = \cos\frac{3\pi}{2}\,\textrm{.}</math>}} | ||
+ | When we draw a line which makes an angle <math>3\pi/2</math> with the positive ''x''-axis, we get the negative ''y''-axis and we see that this line cuts the unit circle at the point (0,-1). The ''x''-coordinate of the intersection point is thus | ||
+ | <math>0</math> and hence <math>\cos (7\pi/2) = \cos (3\pi/2) = 0\,</math>. | ||
[[Image:4_2_3_d.gif|center]] | [[Image:4_2_3_d.gif|center]] |
Current revision
In order to get an angle between 2
![]() ![]() ![]() ![]() ![]() ![]() |
When we draw a line which makes an angle 2
2)=cos(3
2)=0