Why compare the length of the segments in the problem?

Question

Discrete Math

The task under the letter (c).
The answer says the following:

Why is the length of the straight lines that form the main angle compared with the long bisector here?
That is, why do they use in the formula: E(x; y'; x; z') ^ E(x; y'; x; u')
After all, the formula should work correctly without them.

Update: is it used to make the lines that form the main angle have the same length?
If so, would it be possible to change " E(x; y'; x; z') ^ E(x; y'; x; u') ", to E(x; u'; x; z') ?

Answer 1

Offtopic . Mathematics always made me sleepy, my brain started to get lazy, and most importantly, I didn’t understand, and still don’t understand, why is all this necessary? More precisely, why mathematics is needed in principle is understandable, but why people at school and college are hammered into all this heresy, which they will forget in a month, I don’t understand. I don’t understand why everything is so complicated there, and why in the real world should I look for a fucking mountain of abstract points on a spherical horse in a vacuum, is there a straight line on his tail or mane, is his muzzle at an acute angle or not ... I don’t a humanist, but not a 100% technician (although right now I would call web macaques programmers, right?), And I don’t belittle the activities and merits of mathematicians, as well as the benefits of Mathematics in general, I just didn’t ...
Sorry, it hurt.