Besides the fact that u can rearrange the terms so it is the difference of squares.........like relativity theory..................using just the exponents..........2 + 2 + 1 = 5......................the power of 5.........

Why might that be important?  From just a conceptual point of view...........in relativity?............For two things to be compared..........................they have to be viewed from a parameter........pick one parameter............


But 1² is just 1, so:

x² + y² = 1
(the equation of the unit circle)

Also, since x=cos and y=sin, we get:

(cos(θ))² + (sin(θ))² = 1

a useful "identity"