2. Projection – Computing the projection
2.B Computing the projection
Now that we have a plot, we can finally start computing the projection. There are two obvious ways to do
this: using vectors and using trigonometry. Since trigonometry approach is easier to understand, I will leave
the vector approach for the Appendix A. But now let us begin.
Let’s compute the yproj first and after that we can use the same idea for xproj. Firstly we define two triangles:
⊿CAP, where A is the point which is below P and lies on z-axis; and ⊿CBY, where Y is yproj and B is the point
which is below Y and lies on z-axis. You can see the triangle in the Picture 9.
Picture 9: Triangles ⊿CAP and ⊿CBY
From the picture you can notice that both triangles share two angles: the right angle (90°) and the angle
between P and z-axis. In other words:
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