:





:

1.

2.

3.

= ? <N>

n =1 n = 2 n = 3



­ :



_

( :)

(1. ) (150,50)-(100,100)

(2. ) (150,50)-(200,100)

(3. ) (100,100)-(200,100)

(=, )

_

= 1  _

_ࠠ



= 2  (50,50)-(150,100)


_ࠠ

= 3

_ _



( ) ( 100,100),20

堠 (100,100),50



 

­ , ­ - .