Lösung 4.3:6b
Aus Online Mathematik Brückenkurs 1
We draw an angle \displaystyle v in the unit circle, and the fact that \displaystyle \sin v = 3/10 means that its y-coordinate equals \displaystyle 3/10.
With the information that is given, we can define a right-angled triangle in the second quadrant which has a hypotenuse of 1 and a vertical side of length 3/10.
We can determine the triangle's remaining side by using the Pythagorean theorem,
which gives that
This means that the angle's x-coordinate is \displaystyle -a, i.e. we have
and thus
