ˆ 90 = 2.

ˆ , : 2 2 .

, = = =1. ˆ 2 .

1) 04

:

2 2 2 2 .

, ˆ . :

2 22 2

= 2 .

1 2 22 2

= 2 2 – 1.

2) 4 2

:

2 2 2 2 .

, ˆ . :

2 22 2

= 2 .

1 2 2

2 2 = 2 2 – 1.

3) 4

.

* Proofs Without Words Roger B. Nelsen.