Processing Math: Done

From Förberedande kurs i matematik 1

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-	{{NAVCONTENT_START}}	+	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
-	<center> [[Bild:4_2_3d.gif]] </center>	+
-	{{NAVCONTENT_STOP}}	+	{{Displayed math||<math>\cos\frac{7\pi}{2} = \cos\Bigl(\frac{7\pi}{2}-2\pi\Bigr) = \cos\frac{3\pi}{2}\,\textrm{.}</math>}}
-	[[Bild:4_2_3_d.gif|center]]	+
		+	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]]

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Current revision

In order to get an angle between 0 and 2, we subtract 2 from 72, which also leaves the cosine value unchanged

cos27=cos27−2=cos23.

When we draw a line which makes an angle 32 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 0 and hence cos(72)=cos(32)=0.