! "#$ %!&'() * + * ,-./0123 45- −∞ ∩ ∪ !"# $%&'(&)*+)'(, ∃ - ∈ ¡ - - + − < . 45-/ "01 2 - 3- = + + +456*7"&8379 !"33:69+4;<= > ?! @ + A 68< B + A -C A 7 @ - DE9 FG @ = > +< > 9! @ CH @ 6I > 2 - 45- G @ A 68 B +< > &= > &CH68G @ & - & J- − = − + A = B 6<2 @ 2 A - 6< B + ¡ KL&CH68 0< - - F - F J− − − + − = 456- 8M6&N6OPQ-2+G @ 3G @ @ Q!H A ?F ! @ = > R+< > CH @ +S A ! @ Q 6 B B + A +! @ G A +<!G @ 3G @ @ Q FTU'6T+G @ 3G @ @ Q %!&7(-.80123 %9:;<=>$?@=:5A=-$B * C=D E :456F E :456 456- 7 @ B 6= > 6< B +CH @ 68 @ Q B 6= A &6 A += @ < + B C A 8I @ FQ+ + = uuuur uuur uuur uuuur G A + + uuuur uuur uuur 456- &CH68 ( ) ( ) - J - F − + − − = &CH68 +4' !"# DVW68*"+)UCH6 &CH68 +4 B 6'3I @ X '+ @ 7 B %9:;<=>$?@==4=>:$B * C=D E :456GF E :456G 456G- !S+6H a r ! @ b r Y A + 0 r Y+< @ &CHG @ 0 A -0+ !S+6H p 2a b= + r r r ! @ q a xb= + r r r 7 @ +< @ &CH 7 @ B 6= > 6< B +CH @ 68 @ Q B 6= A &6 A += @ < + B G A + + uuuur uuur uuur 456G- K > ! @ 3= B 7<Z B &CH68G @ ( ) ( ) - J - F − + − − = [\ A H(:5 * -$ % &'( ) *&' + , ) * % *- ) . % $ % * / .01 ) * + ) % , ) *2 / " / ) *30 % 34 I (JKL MN %!) E '( 45 OP5=> 2 45 .0Q13 .0/Q123 ∪ = −∞A B ( ; 2009) ∩ =A B [12; 25) =A \ B [25; 2009) .0Q123 ∀ ∈ + − ≥¡ 2 A :" x : x x 2 0" 0Q 0Q 0Q 0Q 45 .0/Q13 .0/Q123 ]L6:60<28'&CH68 3 F J 3 + = − + = KL'6C^+!"3?J .0Q123 DS _ @ 6 B < A F.0Q123 ? `S A 62-!H A - ≥ a<286bP ? `S A 62?-!H A - < a<286bP 0QR 0Q 0Q 0Q 0Q 45 .013 S.0/Q123 cC!(&6 ( ) & J - & − = − 0Q 0Q !"# 9CH68G @ + A = B 6<2 @ 2 A - ∈ ¡ Y & J & − = − = K > = B &CH68G @ CH B +& S.0Q123 `S A 6&CH68G @ 686C @ Y > - ≤ 0<28'+)&CH68G @ - < ≤ 0<28'+)&CH68G @ - F< ≤ 0<28'+)&CH68G @ -dF0<28'+)&CH68G @ e:67<%6Z B &= B a 0Q 0Q 0Q 0Q 0Q 0Q 456 .013 3.0Q123 G @ CH B +6 B B = > J G @ CH B +6 B B = > FJ 3.0/Q123 G A B U @ + B QF G A B U @ + B Q G A +<!&QfQg 83.0/Q123 G A += @ <+QJ h= B 6G A +G @ 3G @ @ aQQ 0Q 0Q 0Q 0Q 0Q 0Q 0Q %!) E 7( 456 .013 S.0123 Q Q Q Q Q Q+ + = + + + + + uuuur uuur uuur uuuur uuur uuuur uuur uuuur uuur FQ Q Q Q+ + = + + + uuuur uuur uuur uuuur uuur uuur uuur FQ+ + = uuuur uuur uuur uuuur !G @ Q7 @ 68 B 6Z6 A + S.0123 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 0Q 0Q 0Q 0Q 0Q 0Q 456 .013 S.0Q123 9CH68G @ + A = B Y! @ +G > Y ' 0∆ ≥ 1≠ ± 2 2 4m 4m 1 0− + ≥ 1 ≠ ± 0Q !"# ( ) 2 2m 1 0⇔ − ≥ !H A B 1≠ ± DZ B 2 1 ≠ ± 6G @ &CH68G @ 7<+ A = B S.0Q123 + A &CH68 +4'-= 2 m 2m 8 0+ − = K > &CH68G @ CH B +Z B ?J7 B DH A 6G @ = B + @ 7 B -? 0Q 0Q 0Q 456G .013 S.0123 + A p r ! @ q r +< @ &CH=6 @ 6 B 0 A 6C 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 6CH B +- 1 2 S.0123 C A CH B + FQ+ + = uuuur uuur uuur uuuur !G @ Q7 @ 68 B 6Z6 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 0Q 0Q 0Q 0Q 0Q 0Q 0Q 0Q 456G .013 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 6G @ &CH 68G @ 68H > 6 @ ?- i F 2- 3 2 − DH A ? 6G @ &CH 68G @ 68H > 6 @ ?g- i F 2- 1 2 − 0Q 0Q 0Q 0Q !"# j B + A + > Y A += A << A 6G A 0CH B +CH > 68 B = > 0 A +< > +Z< !"# . 68< B + A -C A 7 @ - DE 9 FG @ = > +< > 9! @ CH @ 6 I > 2 - 45- G. 6 @ ?- i F 2- 3 2 − DH A ? 6G @ &CH 68G @ 68H > 6 @ ?g- i F 2-