0)dt1+t2dtt(15)b:4x(1)=0,y(1)=3ࢳğ(1)หᆘٚӱູ∏7°8∏5+16∏3=0หᆘ۴ູ0,0,0,2,2,°2,°2ࠎЧࢳቆູ1,t,t2,e2t,te2t,e°2t,te°2t෮ၛ๙ࢳູc+ct+ct2+ce2t+cte2t+ce°2t+cte°2t1234567(2)หᆘٚӱູ∏4+4=0หᆘ۴ູ±(1+i),±(1°i)ࠎЧࢳቆູetcost,e°tcost,etsint,e°tsint෮ၛ๙ࢳູcetcost+ce°tcost+cetsint+ce°tsint1234(3)หᆘٚӱູ∏4°4∏3+8∏2°8∏+3=0pหᆘ۴ູ1,1,1±2ippࠎЧࢳቆູet,tet,etcos2t,etsin2tpp෮ၛ๙ࢳູcet+ctet+cetcos2t+cetsin2t1234p(4)หᆘٚӱหᆘ۴ູ1,1±3iؓႋหᆘཟਈູğppppT3i°1°3i°1T°1°3i3i°1T(1,1,1),(1,,),(1,,)2222ppppppppppᄵ๙ࢳູcet(1,1,1)T+cet(cos3t,°1cos3t°3sin3t,°1cos3t+3sin3t)T+cet(°sin3t,°3cos3t+12222232pppp1sin3t,3cos3t+1sin3t)T222(5)หᆘٚӱหᆘ۴ູ1,2,3ؓႋหᆘཟਈູğ(3,2,3)T,(4,1,1)T,(2,2,3)Tᄵ๙ࢳູcet(3,2,3)T+ce2t(4,1,1)T+ce3t(2,2,3)T123p(6)หᆘٚӱหᆘ۴ູ±i,±3ؓႋหᆘཟਈູğppp13Tp13T1iT1°iT(1,3,°,°),(1,°3,°,),(1,i,,),(1,°i,,)22222222ppᄵ๙ࢳູce3t(1,°1)T+ce°3t(1,°1)T+c(cost,1cost)T+c(sint,1sint)T12223242(7)หᆘٚӱหᆘ۴ູ0,2,3ؓႋหᆘཟਈູğ(°1,3,2)T,(°1,1,0)T,(4,3,1)T42
ᄵ๙ࢳູc(°1,3,2)T+ce2t(°1,1,0)T+ce3t(4,3,1)T123(8)หᆘٚӱหᆘ۴ູ3±5iؓႋหᆘཟਈູğ(1,i)T,(1,°i)Tᄵ๙ࢳູce3t(cos5t,°sin5t)T+ce3t(cos5t,°sin5t)T12(9)หᆘٚӱหᆘ۴ູ5,2±iؓႋหᆘཟਈູğ(2,0,°1)T,(20+10i,15°5i,°14°2i)T,(20°10i,15+5i,°14+2i)Tᄵ๙ࢳູce5t(2,0,°1)T+ce(2+i)t(20+10i,15°5i,°14°2i)T+ce(2°i)t(20°10i,15+5i,°14+2i)T123(10)ఊՑٚӱหᆘٚӱູ∏3°5∏2+8∏°4=0หᆘ۴ູ1,2,2ࠎЧࢳቆູet,e2t,te2t෮ၛఊՑٚӱ๙ࢳູcet+ce2t+cte2t123ഡหࢳູAe3tđսೆٚӱॖA=12ၹՎ๙ࢳູcet+ce2t+cte2t+1e3t1232(11)ఊՑٚӱหᆘٚӱູ∏2°5∏+6=0หᆘ۴ູ2,3ࠎЧࢳቆູe2x,e3x෮ၛఊՑٚӱ๙ࢳູce2x+ce3x12ഡหࢳູAxe°xđսೆٚӱॖA=1ၹՎ๙ࢳູce2x+ce3x+xe°x12(12)ఊՑٚӱหᆘٚӱູ∏4+2∏2+1=0หᆘ۴ູi,i,°i,°iࠎЧࢳቆູcosx,xcosx,sinx,xsinx෮ၛఊՑٚӱ๙ࢳູc1cosx+c2xcosx+c3sinx+c4xsinxഡหࢳູx2(Acosx+Bsinx)đսೆٚӱॖA=°1,B=082ၹՎ๙ࢳູccosx+cxcosx+csinx+cxsinx°xcosx123482ᄜႮԚ่ࡱđᄵcosx+xcosx°3sinx+13xsinx°xcosx88(13)ఊՑٚӱหᆘٚӱູ∏2°2∏+2=0หᆘ۴ູ1±i43
ࠎЧࢳቆູexcosx,exsinx෮ၛఊՑٚӱ๙ࢳູcexcosx+cexsinx12ഡหࢳູxex(Acosx+Bsinx)đսೆٚӱॖA=0,B=2ၹՎ๙ࢳູcexcosx+cexsinx+2xexsinx12(14)Ⴎ၂۱ٚӱॖࢳx=tđࡼఃսೆ۱ٚӱđॖy=°t332(15)Ⴎ၂۱ٚӱॖࢳx=0đࡼఃսೆ۱ٚӱđॖࢳy=t+1b3t2.ഡ"(t)൞ٚӱx00+k2x=f(t)ࢳđఃᇏk൞ӈඔđݦඔf(t)ᄝࡗ[0,+1)ഈ৵࿃b൫ᆣૼğ(a)k6=0ൈđٚӱ๙ࢳॖіൕູZtc21"(t)=c1coskt+sinkt+sink(t°s)·f(s)ds;kk0(b)k=0ൈđٚӱ๙ࢳॖіൕູZtx=c1+c2t+(t°s)f(s)ds0ఃᇏc1,c2൞ၩӈඔbRtᆣૼğ(a)k6=0ൈđၞᆣ"(t)=1sink(t°s)·f(s)dsູٚӱx00+k2x=f(t)၂۱หࢳđطఊՑٚ0k0ӱx00+k2x=0๙ࢳູC2x=C1coskt+sinktkܣٚӱ๙ࢳູZtC21"(t)=C1coskt+sinkt+sink(t°s)·f(s)dskk0Rt(b)k=0ൈđၞᆩ"(t)=(t°s)f(s)dsູٚӱx00(t)=f(t)၂۱หࢳđطఊՑٚӱx00=0๙ࢳ00ູx=C1+C2tđܣٚӱ๙ࢳູZt"(t)=C1+C2t+(t°s)f(s)ds0ఃᇏC1,C22Rb3.۳קٚӱx000+5x00+ax0=f(t)đఃᇏf(t)ᄝ(0,+1)ഈ৵࿃đഡ"(t),"(t)൞ഈඍٚӱၩਆ۱ࢳđ12ࠞཋlim["1(t)°"2(t)]թᄝđ൫ҕඔaᄍྸٓຶbt!+1ࢳğy="(t)°"(t)đᄵy൞ఊՑٚӱࢳđหᆘٚӱູ∏3+5∏2+a∏=0đࢳႵ∏=0,∏=1212pp°5+25°4a°5°25°4a2,∏3=2b°5tsqrt4a°25°5tsqrt4a°2525°4a<0đ๙ࢳູy=C1+C2e2cost+C3e2sintđlimyթᄝĠ22t!+1°5t°5t25°4a=0đ๙ࢳູy=C1+C2e2+C3te2đlimyթᄝĠt!+144
25°4a>0đ๙ࢳູy=C+Ce∏2t+Ce∏3tđေlimyթᄝࣇ∏,∏<0đՎൈa>0b12323t!+1ሸഈ෮ඍđa>0b4.ഡa,b൞ӈඔđf(t)൞ࡗ(°1,+1)ഈ৵࿃ݦඔbഡ!(t;ø)൞Ԛᆴ໙ีx00+ax0+bx=0,x(0)=0,x0(0)=f(ø)ࢳđఃᇏø൞၂۱ҕඔb൫ᆣૼğZtx(t)=!(t°ø;ø)dø0൞Ԛᆴ໙ีx00+ax0+bx=f(x),x(0)=0,x0(0)=0ࢳbࢳğսೆဒᆣࠧॖb5.ࢳߞᆒሰᄝቅ༯఼௧ᆒٚӱd2xm+kx=pcos!tdt2qqఃᇏm,k,pބ!൞ᆞӈඔbؓຓࡆੱ!6=kބ!=kਆᇕ҂౦ঃđٳљඪૼఃࢳၩqmmၬđᆃkіൕߞᆒሰܥႵੱbmࢳğٚӱॖ߄ູd2xkp+x=cos!tdt2mmq!6=kൈ๙ࢳູmrrkkpx(t)=C1cost+C2sint+k2cos!tmmm(°!)m(ຓࡆཛ༢ሱಖੱ٤܋ᆒൈđ༢ᆒږႵཋ)q!=kൈđ๙ࢳູmrrrkkpkx(t)=C1cost+C2sint+ptsintmm2kmm(ຓࡆཛ༢ሱಖੱԩႿ܋ᆒሑൈđႄఏ༢ᆒږཋᄹն)6.ᆣૼğӈ༢ඔఊՑཌྟັٳٚӱቆޅࢳx!1ൈႿਬđࣇ༢ඔइᆔA෮Ⴕหᆘ۴ऎႵڵൌbᆣૼğӈ༢ඔఊՑཌྟٚӱቆޅࢳx!1ൈႿਬđࣇٚӱቆࠎЧࢳቆx!1ൈ45
Ⴟਬbૌॖၛܒᄯٚӱቆ၂۱ࠎЧࢳቆೂ༯ğY1(x),···,Yn1(x);···;Y1(x),···,Ynk(x)11kknj°1XxiYl(x)=e∏jx[(A°∏E)i]vljji!i=0ॖေམx!1ൈႿਬđหᆘ۴сྶऎႵڵൌbࢫ༝ี1.ഡᄝࡗ(°1,+1)ഈq(x)∑0đᆣૼఊՑཌྟັُ၂۱٤ޅ0=y)x(q+0y)x(p+00yӱٚٳࢳቋ؟ᆺႵ၂۱ਬb2.ᆣૼఊՑཌྟັٳٚӱy00+p(x)y0+q(x)y=0ޅਆ۱ཌྟܱࢳਬ൞ཌྷࢌհb2ᆣૼğഡy,y൞ਆ۱ཌྟܱࢳđ০Ⴈэߐy(x)=v(x)u(x)ၛࠣv>0đॖၛुu,u൞ٚӱdu+1212dt2Q(t)u=0ཌྟܱࢳđႮज़Чં4.5.2ॖ෮ေࢲંb3.ഡັٳٚӱd2x+P(t)x=0dt2ఃᇏP(t)൞t৵࿃2ºᇛ௹ݦඔđطડቀn20༯૫҂ൔӮ৫ğ(n+")2
2ºbၹn+"ՎࢲંӮ৫bੂࢫ༝ี1.ࢳ༯ਙшᆴ໙ีğ(1)y00+y=x;y(0)=2,y(º)=1Ġ2(2)y00°3y0+2y=ex,y(0)=0,y(1)=0Ġ46
(3)x2y00°3xy0+3y=0,y0(1)+y(1)=°2,2y0(2)°y(2)=0bࢳğ(1)ఊՑٚӱหᆘٚӱູ∏2+1=0หᆘ۴ູ±iࠎЧࢳቆູcosx,sinxఊՑٚӱ๙ࢳູc1cosx+c2sinxഡหࢳູAxđսೆٚӱA=1ၹՎ๙ࢳູc1cosx+c2sinx+xᄜ০Ⴈшᆴ่ࡱy(x)=2cosx+(1°2)sinx+xº(2)ఊՑٚӱหᆘٚӱູ∏2°3∏+2=0หᆘ۴ູ1,2ࠎЧࢳቆູex,e2xఊՑٚӱ๙ࢳູcex+ce2x12ഡหࢳູAxexđսೆٚӱA=°1ၹՎ๙ࢳູcex+ce2x°xex12ᄜ০Ⴈшᆴ่ࡱy(x)=1ex+1e2x°xex1°ee°1(3)ႮEulerٚӱࢳم๙ࢳູcx+cx312ᄜႮшᆴ่ࡱy(x)=°xb2.ᆣૼшᆴ໙ี8º(s°º)5p3º(2)F(s)=5đs>°44(s+4)2(3)F(s)=3ºđs>°2(s+2)2+9º2pp(4)F(s)=22s+52đs>°1(2s+1)2+1622.࠹ෘ༯ਙݦඔF(s)ঘ൦эߐğ(1)F(s)=3,(2)F(s)=s°12s°4(s+1)2(3)F(s)=s+2,(4)F(s)=1s2+4s+5s2°43(5)F(s)=s,(6)F(s)=5°2s(s°4)4s2+7s+103(7)F(s)=s,(8)F(s)=s(s2+k2)2s4+4a4ࢳğ(1)f(t)=3e2t2(2)f(t)=(1°2t)e°t48
(3)f(t)=e°2tcost(4)f(t)=1sh(2t)2(5)f(t)=e4t(1+12t+24t2+32t3)3°7t3°7t3(6)f(t)=°2e2ch(t)+8e2sh(t)22(7)f(t)=tsin(kt)2k(8)f(t)=1eatcos(at)+1e°atcos(at)223.Ⴈঘ൦эߐٚمࢳ༯ਙԚᆴ໙ีğ(1)y00+4y0+4y=t2;y(0)=y0(0)=0;(2)x00+6x0+34x=30sin2t;x(0)=x0(0)=0(3)x00+!2x=Fsin!t,x(0)=x0(0)=0,!6=0;000(4)y(4)+2y00+y=4tet,y(0)=y0(0)=y00(0)=y(3)(0)=0.ࢳğ(1)ᄝٚӱਆҧ౼ঘ൦эߐđѩ࠺L{f(t)}=Y(s)đ22sY+4sY+4Y=.s32෮ၛY=2đy(t)=°te°2t°3e°2t+t°t+3s3(s2+4s+4)48428(2)ᄝٚӱਆҧ౼ঘ൦эߐđѩ࠺L{x(t)}=X(s)đ260sX+6sX+34X=.s2+4෮ၛX=60đx(t)=60(e°3tcos(5t)°2e°3tsin(5t)°cos(2t)+5sin(2t))(s2+4)(s2+6s+34)17452(3)ᄝٚӱਆҧ౼ঘ൦эߐđѩ࠺L{x(t)}=X(s)đ22!sX+!0X=F0s2+!2.෮ၛ!=!ൈީđX=F!0đx(t)=F0sin(!0t)°F0tcos(!0t)b00(s2+!2)22!22!000!6=!ൈީđX=F(1°1)!đx(t)=F0(!0sin(!t)°!sin(!0t))b00s2+!2s2+!2!2°!2!0(!2°!2)000(4)ᄝٚӱਆҧ౼ঘ൦эߐđѩ࠺L{f(t)}=Y(s)đ424sY+2sY+Y=.s2෮ၛY=4đy(t)=2tcost°6sint+4tbs2(s4+2s2+1)4.Ⴕ၂ᇕԯѷࡨᆑఖ০Ⴈ൞ᯒކᆒჰbᄝඣ૫ഈԯุॖၛቔູ၂۱ቅᆒሰđఃᇉਈູMđ࣑༢ඔູKđቅ༢ඔູRđࡨᆑఖᄵ൞ڸᄝԯุഈᆒሰđᇉਈູmđ࣑༢ඔູkbԯุ໊၍X(t)ބࡨᆑఖ໊၍x(t)ડቀᄎٚӱ80)Ġ(2)(2x+1)2y00°4(2x+1)y0+8y=0Ġ2(3)dx+x=1Ġdt21+cos2t2(4)t2(t+1)dx°t(2+4t+t2)dx+(2+4t+t2)x=°t4°2t3Ġdt2dt2(5)tdx°(2t+1)dx+(t+1)x=(t2+t°1)e2tĠdt2dt32(6)(1°t2)dx°tdx+dx=0bdt3dt2dtࢳğ(1)x=etđᄵy+4y+13y=0đหᆘٚӱ∏2+4∏+13=0đ∏=°2±3iđႿ൞y=e°2t(ccos3t+ttt1c2sin3t)đ෮ၛc1cos(3lnx)+c2sin(3lnx)y=.x2(2)2x+1=t,ᄵt2y°2ty+2y=0đᄜt=euđᄵหᆘٚӱູ∏(∏°1)°2∏+2=0đࢳ∏=1,2btttႿ൞y=ceu+ce2u=ct+ct2=c(2x+1)+c(2x+1)2.121212(3)ఊՑٚӱหᆘٚӱູ∏2+1=0đႿ൞ఊՑٚӱႵ๙ࢳx(t)=ccost+csintđಖުႮӈඔэၳ܄12ൔႵZtsin(t°s)x(t)=c1cost+c2sint+ds.t1+cos2s0(4)ૌ൮༵ھٚӱหࢳđҩࢳྙൔູx=at2+bt+cđսೆٚӱa=1,c=0bႿ൞Ⴕหࢳx=t2+btbႮՎૌᆩx=t൞ཌྷႋఊՑٚӱࢳbૌᄜႨࢆࢨمটఊՑٚӱ๙ࢳđࠧഡࢳູx=tu(t)đսೆٚӱt3[(t+1)u°(t+2)u]=0đv=uđᄵࢳv=C(t+1)etđႿ൞u=Ctetđtttt෮ၛቋᇔૌٚӱ๙ࢳູx=t2+Ct+Ct2et.12(5)ૌ൮༵ھٚӱหࢳđҩࢳྙൔູx=(at+b)e2tđսೆٚӱa=1đb=0đႮՎᆩห50
ࢳູx=te2tbᄜఊՑٚӱਆ۱ཌྟܱࢳđᇿၩఊՑٚӱູ0dx2dxdx2dxdxt°(2t+1)+(t+1)x=t(°)°(t+1)(°x)=0,dt2dtdt2dtdtႿ൞ಸၞหࢳx=CetđಖުႨࢆࢨمđഡx=C(t)etđսೆٚӱđࢳx=t2etbႿ൞ቋᇔٚӱ12ࢳູx=(C+Ct2)et+te2t.122P(6)y=dxđᄵھٚӱູ(1°t2)dy°tdy+y=0đႨૢࠩඔمࢳđഡࢳູy=atnđսೆٚdtdt2dtn∏0nӱđᄵႵa=n°3abႿ൞ૌႵ๙ࢳy=ct+c(1°1t2°Pk∏2(2k°3)!!t2k)bႮՎჰটٚӱnnn°2122(2k)!!๙ࢳູ1X(2k°3)!!t2k+1x=c+ct2+c(t°t3°k∏2).0126(2k)!!2k+12.ԛ༯ਙັٳٚӱᄝx=x0ԩᅚषਆ۱ཌྟܱૢࠩඔࢳđѩཿԛཌྷႋ־܄ൔğ(1)y00°xy0°y=0,x=0;(2)y00°xy0°y=0,x=1;003(3)(1°x)y00+y=0,x=0;(4)dy+xy=0,x=0;0dx302(5)xdy+4dy+xy=0,x=0;(6)y00+(sinx)y=0,x=0.dx2dx00ࢳğPP(1)y=axnđսೆٚӱ(a(n+2)(n+1)°an°a)xn=0đႿ൞־܄n∏0nnn+2nnan°2ൔan=nb෮ၛೂݔٳљ౼(a0,a1)=(1,0)ބ(a0,a1)=(0,1)đૌॖၛਆ۱ཌྟܱࢳXx2ky1=,(2k)!!k∏0Xx2k+1y2=.(2k+1)!!k∏0PP(2)y=a(x°1)nđࡼٚӱཿູy00°(x°1)y0°y0°y=0đսೆٚӱ(a(n+2)(n+1)°n∏0nnn+2an°a(n+1)°a)(x°1)n=0đႿ൞־܄ൔa=an°1+an°2b෮ၛೂݔٳљ౼(a,a)=(1,0)nn+1nnn01ބ(a0,a1)=(0,1)đૌॖၛਆ۱ཌྟܱࢳbPP(3)y=axnđսೆٚӱ(a(n+2)(n+1)°a(n+1)n+a)xn=0đႿ൞־n∏0nnn+2n+1nan°1(n°1)(n°2)°an°2܄ൔan=n(n°1)b෮ၛೂݔٳљ౼(a0,a1)=(1,0)ބ(a0,a1)=(0,1)đૌॖၛਆ۱ཌྟܱࢳbPP(4)y=axnđսೆٚӱ6a+[a(n+3)(n+2)(n+1)+a]xn=0đႿ൞n∏0n3n∏1n+3n°151
־܄ൔa3=0,an=°an+4(n+4)(n+3)(n+2)(n∏0)b෮ၛೂݔٳљ౼(a0,a1,a2)=(1,0,0)ބ(a0,a1,a2)=(0,1,0)đૌॖၛਆ۱ཌྟܱࢳbPP(5)y=axnđսೆٚӱ4a+[a+(n+4)(n+1)a]xn=0đႿ൞־܄n∏0n1n∏1n°1n+1ൔa=0,a=°an(n∏0)b෮ၛೂݔٳљ౼a=1ބa=2đૌॖၛਆ۱ཌྟܱ1n+2(n+5)(n+2)00ࢳb3.ؓႿ༯ਙԚᆴ໙ีԛy00(x),y(3)(x)ބy(4)(x)đՖطཿԛཌྷႋԚᆴ໙ีࢳᄝxীࠩඔ0000భ5ཛğ(1)y00+xy0+y=0;y(0)=1,y0(0)=0;(2)y00+(sinx)y0+(cosx)y=0;y(0)=0,y0(0)=1.ࢳ:(1)Ⴎٚӱđૌᆩy(k+2)=°xy(k+1)°(k+1)y(k),Ⴟ൞ႮԚᆴđૌy00(0)=°1,y(3)(0)=0ބy(4)(0)=3đႮՎx2x4y=1°++···,28(2)ႮٚӱބԚᆴđૌႵy00(0)=0đؓٚӱ၂ࢨඔđy(3)(0)=°2ބy(4)(0)=0đႮՎx3y=x°+···.34.ࢳHermiteٚӱğy00+2xy0+∏y=0,(°10ൈđr1=i∏,r°2=°i∏đٚӱ๙ࢳູy=C1cos∏t+C2sin∏tđսೆшᆴ่ࡱॖ8p0༯૫҂ൔӮ৫ğ2g(x1)°g(x2)2(n+")<<(n+1),(°1>°x0+y0+z0°x+2z=e°t>>>:x0+y0°z+x+2y=3e°tࢳğ8>>x=1Ct2e°t°Cte°t+Ce°t+5te°t°t2e°t+1t3e°t><212324y=°Cte°t+Ce°t+2te°t°3t2e°t>>124>:z=Ce°t+3te°t12ၞᆩޙ(°1,0)໗ק҂ࡶ࣍໗קb6.ᆣૼшᆴ໙ี80,q>0ൈđਬࢳ൞ࡶࣉ໗קb(2)p>0,q=0ࠇp=0,q>0ൈđਬࢳ൞໗קđ҂൞ࡶࣉ໗קb(3)ᄝః౦ྙ༯đਬࢳ൞҂໗קbᆣૼğഡ∏1,∏2ູAਆหᆘ۴đᄵğ∏1+∏2=°p,∏1∏2=q(1)p>0,q>0ᄵ∏1,∏2ູਆ۴ൌڵࠇ၂ؓൌູڵ܋ᣢྴ۴đႮק5.1.1ᆩđਬࢳࡶࣉ໗קb(2)p>0,q=0ᄵ∏1,∏2ק໗ࣉࡶ٤đק໗ࢳਬđᆩ1.1.5קႮđ۴ਬ۴၂ᆞ၂ູљٳbp=0,q>0ᄵ∏1,∏2ູਆ܋ᣢՂྴק໗ࣉࡶ٤đק໗ࢳਬđᆩ1.1.5קႮđ۴b(3)(1)(2)ק໗҂ࢳਬđᆩ1.1.5קႮđᆞູൌ၂۱Ⴕഒᇀ۴ᆘหđ༯ྙ౦ఃᄝđ༅ٳb4.ษંົٚӱx0=y°xf(x,y),y0=°x°yf(x,y)ਬࢳ໗קྟđఃᇏݦඔf(x,y)ᄝ(0,0)ڸ࣍൞৵࿃ॖັbࢳğf(x,y)ᄝ(0,0)ڸ࣍৵࿃ॖັđᄵf(x,y)ᄝ(0,0)၂ཬਣთଽॖ၂ࢨ࣍රᅚषູğpf(x,y)=f(0,0)+fx(0,0)x+fy(0,0)y+o(x2+y2)ᄵჰົٚӱ၂ࢨཌྟ࣍රٚӱູx0=y°f(0,0)xy0=°x°f(0,0)y61
ᄵႮഈีٳ༅ॖᆩđf(0,0)>0ൈđਬࢳࡶࣉ໗קbf(0,0)0ൈđਬࢳ໗ק໗ࣉࡶ٤đקbf(0,0)>0ൈđਬࢳ҂໗קb5.ഡݦඔg(x)৵࿃đx6=0ൈxg(x)>0.൫ᆣٚӱx”+g(x)=0ਬࢳ൞໗קđ҂൞ࡶࣉ໗קbRxᆣૼğ໗קྟᆣૼđ߄ູٚӱቆđѩ౼V=1y2+f(s)ds20קႨ০ྟק໗࣍ࡶ٤ၬᆣૼb6.ษં༯ਙٚӱਬࢳ໗קྟğ(1)x0=°y°xy2,y0=x°x4y(2)x0=°y3°x5,y0=x3°y5(3)x0=°x+2x(x+y)2,y0=°y3+2y3(x+y)2(4)x0=2x2y+y3,y0=°xy2+2x5ࢳğ(1)122V(x,y)=(x+y)>02dV(x,y)2242=°(xy+xy)<0dtਬࢳࡶࣉ໗קb(2)V(x,y)=(x4+y4)>0dV(x,y)88=°4(x+y)<0dtਬࢳࡶࣉ໗קb(4)N={(x,y):x>0,y>0}V(x,y)=x2y462
dV(x,y)2773=2xy+8xydtdV(x,y)NଽႵV(x,y)>0,>0,шࢸഈႵV(x,y)=0,dtܣਬࢳ҂໗קb7.ษંa౼ޅᆴൈđٚӱቆ80,3ีٳ༅đਬࢳ҂໗קb(2)a=0,V(x,x)=(x2+x2)>0ᄵ1212dV(x,y)=2(x4+x4)>0,ܣਬࢳ҂໗קbdt12(3)a<0,3ีٳ༅đਬࢳࡶࣉ໗קb8.࣮ࢨັٳٚӱx0=y,y0=°1+x2ਆ۱ޙ໗קྟbࢳğၞᆩٚӱቆਆ۱ޙູ(1,0),(°1,0)b(1)ؓႿޙ(1,0)bx1=x°1,y1=yᄵཌྷॢࡗ(x,y)ᇏޙ(1,0)ؓႋႿཌྷॢࡗཌྷॢࡗ(x1,y1)ᇏޙ(0,0)bႵğ80,y1>0},V(x1,y1)=x1y1ᄵႵğdV(x1,y1)2=3x1y1+x1y1dtdV(x1,y1)ᄝNഈႵğV(x1,y1)>0,dt>0ᄝ@NഈႵğV(x1,y1)=0Ⴎק໗҂)0,1(ޙğᆩקקb(2)ؓႿޙ(°1,0)bx2=x+1,y2=yᄵཌྷॢࡗ(x,y)ᇏޙ(°1,0)ؓႋႿཌྷॢࡗཌྷॢࡗ(x2,y2)ᇏޙ(0,0)bႵğ80dµr=1,dt:0,r=0൫ቔԛჰڸ࣍ཌྷđѩ࣮ޙr=0໗קྟᇉbčĎ2.؎༯ਙٚӱఅ(0,0)োđѩቔԛھఅڸ࣍ཌྷb(1)x0=4y°x,y0=°9x+y(2)x0=2x+y+xy2,y0=x+2y+x2+y2(3)x0=2x+4y+siny,y0=x+y+ey°1(4)x0=x+2y,y0=5y°2x+x3(5)x0=x(1°y),y0=y(1°x)ࢳğ(1)ᇏྏb(2)҂໗קචཟࢲb(3)λb(4)λb(5)҂໗קྒྙࢲb3.൫ಒקٚӱቆ80đթᄝ±>0đ||x1||<±Ⴕ||x1(t)=√(t)√°1(t)x1||<"b෮ၛؓႿ000၂xđሹթᄝx1đડቀx1=Cxđ||x1||<±đପહႵ0000)||x(t)||=||C√(t)√°1(t)x1||0ބt0∏0b҂ં±>0؟હཬđሹթᄝx0đෙಖ||x0||<±đ൞(4.1)Ⴕၛx(t0)=x0ູԚᆴࢳx(t,t0,x0)ᄝtႿଖt1(∏t0)ൈႵ||x(t1,t0,x0)||∏"ପહx1=Cxđᄵ0"01°11C||x(t)=√(t)√(t0)x0||=||x(t)||>C"Ӂള؛b෮ၛਬࢳ໗קb65
(2))ؓႿၩ۳קt0∏0đթᄝ±>0đᆺေx0ડቀ||x1||<±0༢(4.1)ડቀԚᆴ่ࡱx1(t)=xࢳx1=x1(t,t,x)ьႵ0000limx1(t,t,x1)=000t!+1෮ၛؓႿ၂xđሹթᄝx1đડቀx1=Cxđ||x1||<±đପહႵ0000)limx(t,t,x)=Climx1(t,t,x1)=00000t!+1t!+1(ؓႿ၂x(t)ડቀlimt!+1x(t)=0đପહؓԚᆴޓཬx(t)္ડቀlimt!+1x(t)=0bൈႮႿlimt!+1x(t)=0đᄵ၂x(t)ႵࢸđᄵႮ(1)ᆩਬࢳ໗קb෮ၛਬࢳࡶ࣍໗קb2.ഡඔᆴݦඔf(x,t)ᄝთ{(t,x):t∏0,|x|0,x2<0ٚӱડቀԚᆴ่ࡱx(0)=x1,x(0)=x2ࢳđt!+1ൈႿਬđᄵਬࢳ൞ࡶࣉ໗קbᆣૼğഡԚᆴx1,x2ؓႋࢳٳљູ"1(t),"2(t)b(1)؎ğ00,{t}1,t!1(j!1)st|"(t)|>"bၹູlim"(t)=0đ෮ၛթᄝଖ0jj=1jj0t!11۱t0đt>t0ൈđ|"1(t)|<"0đࠧթᄝi>0đj>iൈđ|"(tj)|>|"1(tj)|đطx0x0>x2ൈđၛx0ູԚᆴࢳ"(t)t!+1ൈႿਬb౼±=min{x1,°x2}đᄵ|x0|<±ൈđၛx0ູԚᆴࢳ"(t)ડቀlimt!1"(t)=0đܣਬࢳ൞ࡶ࣍໗קb3.ॉ੮༯ਙਆ۱ٚӱቆdX={A+B(t)X}dtdX=AXdtR1ఃᇏA൞ӈइᆔđB(t)൞ᄝt∏0ഈ৵࿃इᆔݦඔડቀ|B(t)|dt<10ᆣğೂݔު၂۱ٚӱ၂్ࢳᄝt∏0ഈЌӻႵࢸđᄵభ၂۱ٚӱ၂్ࢳᄝt∏0ഈ္ЌӻႵࢸb66
ᆣૼğ၂۱ٚӱቆൡކԚᆴ่ࡱX(t0)=X0ࢳॖіൕູğZtX(t)=©(t)©°1(t)X+©(ø)©°1(ø)B(ø)X(ø)dø(t∏0)00t0ఃᇏ©(ø)൞۱ٚӱቆൡކԚᆴ่ࡱ©(t0)=Eࠎࢳइᆔbၹູ۱ٚӱ၂్ࢳᄝt∏0ഈЌӻႵࢸđ©(t)©°1(t)X൞۱ٚӱቆડቀԚ่ࡱX(t)=XࢳđܣթᄝᆞӈඔMđ0000||©(t)||||©°1(t)||||X||∑M,||©(ø)||||©°1(ø)||∑M(t∏0)00ܣॖğZt||X(t)||∑M+M||B(ø)||||X(ø)||dø(t∏0)t0ႮGrowall҂ൔđᄵႵğRtM||B(ø)||dø||X(t)||∑Met0(t∏0)R+1RtMhၹູ||B(ø)||dø<+1෮ၛ||B(ø)||døႵࢸđഡູhđᄵႵğ||X(t)||∑Me(t∏0)ࠧ၂۱ٚ0t0ӱቆ၂్ࢳ൞Ⴕࢸb4.ॉ੮༯ਙਆ۱ٚӱቆdX=AX+R(t,X)dtdX=AXdtఃᇏA൞ӈइᆔđR(t,X)ᄝ{(t,X):t∏t0,||X||||)t(X||đൈ±>||X||đ"=±ᄝթđ0>"۳bMeMh05.ഡཌྟັٳٚӱx0=ax+by,y0=cx+dyၛ(0,0)ູۚࢨఅđ൫ቔԛఃཌྷbčĎ6.ॉ੮ࢨٚӱቆ80ູӈඔĎᇀഒႵ၂۱о݅b68'