Solution 4.3:4b

From Förberedande kurs i matematik 1

(Difference between revisions)
Jump to: navigation, search
m (Lösning 4.3:4b moved to Solution 4.3:4b: Robot: moved page)
Line 1: Line 1:
-
{{NAVCONTENT_START}}
+
If we once again use the Pythagorean identity we get
-
<center> [[Image:4_3_4b.gif]] </center>
+
 
-
{{NAVCONTENT_STOP}}
+
 
 +
<math>\cos ^{2}v+\sin ^{2}v=1\quad \Leftrightarrow \quad \sin v=\pm \sqrt{1-\cos ^{2}v}</math>
 +
 
 +
 
 +
Because the angle v lies between
 +
<math>0</math>
 +
and
 +
<math>\pi </math>,
 +
<math>\text{sin }v</math>
 +
is positive (an angle in the first and second quadrants has a positive
 +
<math>y</math>
 +
-coordinate) and therefore
 +
 
 +
 
 +
<math>\sin v=+\sqrt{1-\cos ^{2}v}=\sqrt{1-b^{2}}</math>

Revision as of 11:42, 29 September 2008

If we once again use the Pythagorean identity we get


\displaystyle \cos ^{2}v+\sin ^{2}v=1\quad \Leftrightarrow \quad \sin v=\pm \sqrt{1-\cos ^{2}v}


Because the angle v lies between \displaystyle 0 and \displaystyle \pi , \displaystyle \text{sin }v is positive (an angle in the first and second quadrants has a positive \displaystyle y -coordinate) and therefore


\displaystyle \sin v=+\sqrt{1-\cos ^{2}v}=\sqrt{1-b^{2}}