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`S A 62-!H A - ≥ a<286bP ? `S A 62?-!H A - < a<286bP 0QR 0Q 0Q 0Q 0Q 45 .013 S.0/Q123 cC!(&6 ( )  & J - & − = −  0Q 0Q  !"#  9CH68G @ + A = B 6<2 @ 2 A - ∈ ¡ Y  & J  &    − =  − =  K > = B &CH68G @ CH B +& S.0Q123 `S A 6&CH68G @ 686C @ Y >  - ≤ 0<28'+)&CH68G @    - < ≤ 0<28'+)&CH68G @    - F< ≤ 0<28'+)&CH68G @  -dF0<28'+)&CH68G @  e:67<%6Z B &= B a 0Q 0Q 0Q 0Q 0Q 0Q 456 .013 3.0Q123 G @ CH B +6 B  B = > J G @ CH B +6 B  B = > FJ 3.0/Q123 G A  B U @ + B QF G A  B U @ + B Q G A +<!&QfQg 83.0/Q123 G A += @ <+QJ h= B 6G A +G @ 3G @  @ aQQ  0Q 0Q 0Q 0Q 0Q 0Q 0Q %!) E 7( 456 .013 S.0123     Q Q Q Q Q Q+ + = + + + + + uuuur uuur uuur uuuur uuur uuuur uuur uuuur uuur     FQ Q Q Q+ + = + + + uuuur uuur uuur uuuur uuur uuur uuur     FQ+ + = uuuur uuur uuur uuuur !G @ Q7 @ 68 B 6Z6 A + S.0123 G A 3 A YG A CH @ 68 @  B 6= A &6 A +3I @  a 3 3  + A    + + uuuur uuur uuur F MO uuuur F a 3 3  a 3 0Q 0Q 0Q 0Q 0Q 0Q 456 .013 S.0Q123 9CH68G @ + A = B Y! @ +G > Y ' 0∆ ≥  1≠ ±  2 2 4m 4m 1 0− + ≥  1 ≠ ±  0Q  !"#   ( ) 2 2m 1 0⇔ − ≥ !H A  B  1≠ ± DZ B 2 1 ≠ ± 6G @ &CH68G @ 7<+ A = B  S.0Q123 + A &CH68 +4'-= 2 m 2m 8 0+ − = K > &CH68G @ CH B +Z B ?J7 B  DH A 6G @ = B + @ 7 B -? 0Q 0Q 0Q 456G  .013 S.0123 + A  p r ! @  q r +< @ &CH=6 @ 6 B 0 A 6C B +0+ p mq= r r   ⇔  2a b+ r r  a xb+ r r  (2 m)a (1 mx)b 0⇔ − + − = r r r DG @ !S+6H a r ! @  b r Y A + 0 r ! @ Y+< @ &CH= 2 m 0 1 mx 0  − =  − =  K > = B 6CH B +- 1 2  S.0123 C A CH B +     FQ+ + = uuuur uuur uuur uuuur !G @ Q7 @ 68 B 6Z6 A + G A 3 A YG A CH @ 68 @  B 6= A &6 A +3I @  a 3 3  + A    + + uuuur uuur uuur F MO uuuur F a 3 3  a 3 0Q 0Q 0Q 0Q 0Q 0Q 0Q 0Q 456G .013 DH A  1≠ ± + A  ' ∆  2 4m 4m 1 0− + ≥  ( ) 2 ' 2m 1 0⇔ ∆ = − ≥ !H A  B  1 ≠ ±     DZ B 2  &CH  68G @   7<  + A    = B   &Z  3= B 6 − = = − + 1 2 1 3 x ; x m 1 m 1 !H A  B  1 ≠ ±  DH A         6G @  &CH  68G @   68H >  6 @   ?-  i  F     2- 3 2 −   DH A       ?  6G @  &CH  68G @   68H >  6 @   ?g-  i  F     2- 1 2 −  0Q 0Q 0Q 0Q  !"#  j B + A + > Y A += A << A 6G A 0CH B +CH > 68 B = > 0 A +< > +Z<  !"# . 68< B + A -C A 7 @ -  DE 9 FG @ = > +< > 9! @ CH @ 6 I > 2 -  45- G. 6 @   ?-  i  F     2- 3 2 −   DH A       ?  6G @  &CH  68G @   68H >  6 @   ?g-  i  F     2-