! " # $ %& '( ) * )#+",-$ ( ) . ) /0 , ( 1 (2 34 ) 5 6 , 7 )8& 9 4 : 1 /: # ; < => + 1 /?; / / =1 7 / 0yx3:d 1 =+ 0yx3:d 2 =− !" #$%!& " ' #(%)!∆$(*#(+,%-"./!∆$( 2 3 $ 01 23&!4!5 (6!!4!73$8!" (% 8!" ' 98!-3):%-%! (6!';<"9$⊥" $(⊥(7 3):-%!=!>383): (6!?;<"9"./!34!*$( 7,3@2)A+,!B C5! 2 3xy:dA 1 −=∈ 3xy:dC,B 2 =∈ )3c,c(C),3b,b(B),3a,a(A − %01 D ( ) 3)ac(,acAC +−= %E!+!F+!B" G )3,1(u −= H∆$(*#(I$J/" !6" #$$⊥" a2c0)ca(3ca0u.ACuAC −=⇔=++−⇔=⇔⊥ )3a2,a2(C −− D ( ) ( ) v)3,1(//3)a2b(,a2bCB,3)ab(,abAB =++=+−= H∆$(*#( 2 a b0v.ABCBAB −=⇔=⊥ ) 2 3a , 2 a (B −− K2 2 3 2 3a3 Sa3 4 a27 4 a9 BC,3a 4 a3 4 a9 AB 2 ABC 2222 ===+==+= 2AC)1,3(AC)2, 3 2 (C),1, 3 1 (A 3 1 a 3 1 a 0a2 =−−=−−−=→←= > H2!23 ) 2 3 , 32 1 (I −− 73$-4J/ 1 2 AC R == !2+ , 1) 2 3 y() 32 1 x( 22 =+++ " $ " ' (