j-g-gP&or vin*H PHuc rnuoxc rgpr it- xoiv ruAm Hec zoto- zott on rHr ruAo sAr cnuytl un ,on # :. UON THI : TOAN KIIOI D ( rhd,i gian tdm tai', tio)n,;n =* (l) Cf,u I( Z.O aiOm ;, Cho phuorr* ,r,ni, (x - 3X.r + r; _ a_u1rrr _f_ 3 l, Giai nhuyng trinh (t ) vcri m = *3 2, Tim m c16 phuorg i"i,rriij .o ngrriOn, Ciu II( 2.0 eli6m ). Tim m d6 phuong trinh c6 hai nghi.m x', x2tho6 rnfrn; xt * x2 * 2*,*, = ] . -2 CAu IV( 2.0tti6m ). Trong mpt phing tga d6 D6cac vu6ng goc oxy .r' , fliff;'^;::;fii'4,;liol "a il,i duong *iq ran r,qr chua c6c duong cao ha Tinhdi€nd.;;; giitcABc rgringldL: r* 2v+t=ovd 3x+ y-r,=0 2. Cho duonp rr.,,"l rni ^: -^,- :x ld,i,-*ff iJ;*JT,'J'*-T;|,;, ;{:; ;(,;;; -, =, Yoi a' b' c td: so tn#Lu:-ry,n"+uf g,ine:Ug:o6 + bc + ca = abc . Chung rninh ring: l b' +_2at * J rt * zb= {r. " h, ciu vI( r.o tri6nr). qb - 7 __- * ;i = f il[Vtt'i]T]-r$:' thuc satr kh6ng php thu6c x : A:sin2 xtan2 x+ 4sin2 x- tan2 x +3cos2 x Tim m ae u6t phuong tri'h sau dfng v6i moi x: (m +1)x2 + 2rnx+ 2 > 0 IL[{; "D I ,, t_ 07 rU VA TIIANG DIBM HTIONG nAm cHAn,r 0,5 0,5 Di 0,5 4,25 0,25 0,25 0,25 0,25 0,,25 0,25 0,25 0,25 0,25 4,25 l,E4t t : .l-7 - 2. -3 > 0. Phu<yn trinh tro thAnh:r2 +4r+3=0 ft=-l €l- (loai)I(L: tl = -1 L- 2,Ddt"t:{:_2*_3 > 0. Phucrn trinh tro thdnh: l2 +4t-m=0em-1.+4t b i en tni en qua nam-ffi7ffi ** ygglBT ta c6 m> 0 l, Ta c6: Ei€u kiQn: x > 4 Bphuong trinh dd cho tuong dugrg v6i : *x>5 bdt uong trinh lu6q nghiQm dirn *4<xsS, bdtphuong <+ l0*.67<x<5 5 :lg{,1) vd (2) x > l0 _ $4 ?, T1ptg) :gll@,rtrh tr6 rlrdrh j + rt 1 4 <+t-1+y=1-2x Th <+ c T L V x x ao pr =l -*3 2)taducrc: x, +2x_3=0 Pt c6 hai nshi€ lt, ": fni va cni ruri l,=6ln+ 12 > 0 a m2 _2 Theo bdi ra: r, * x, -2x,.", = * c> -2(m+ 3) _ 2(nf _3F 2 / L\"o J, 2 a4m2 +4m+l=0c> *=_! 2 p6i ctricu di€u kiQn (t), m= - I thod nrdn I,Euong thing AC di qua A ua *.anffi 2:0 ldm vdc to ph6p tuy6n n€n c6 pt:2xiy * Ducrng thing AB di qua A vd nh{n ir(t;_Z) l:0 ldm vdc to ph6p tuy6n n6n c6 pt: x _3y * Toa d6 B ld nghidm cria h6: x*2y +l=0 x-3y-l=0 =+ B(-5;-2) 'rea d$ c ld nghiQm cua he{:' + | -t_= 0 = c; ltxl y-'2=0 Gqi BI{ ld duong cao hs tu B. Ta c6 BH = d(B;AC) =]jq ;t -31= ,1 *F .% V) V5 AC= 2 6. V4y S :!.AC.BH =14 (dvdt) KL: trdn c6 tdm I(-3;2), b'n kinh R = 4 TFI1: Gii sri ducrng thing qua E kx - v - k + 5 : 0.(a). E€ duong thrng a lftidp tuy€-n ""u icl trri'aia"'iig"la, d(l;a) = ft l-:,t-2-k+51 _j _,, _______ + = 4 (D k _ _ ffi = 4 <+ k = VAy pftr : y : -7124.(x_ t) + S Vfiy x - I : 0 ld tt tfr* Z .iraauonffi KL D4t 1= *;l =.v;] = z SU) ra x. y, ,rO rUx *y * z:l q b "c Theo Bunhia : 3(x2 +Zyr)=3(xt + y, + yt)>(* + y + y)2 + +2y' J;' +2-' - {fr +zy + y +zz + z +zg > Jl J3 x' +2y2 + J^ y- +lz Ddu bdng xAy ra khi u5 r1",1L111 u: 6 : .l .) , sin';r , sin2x A=stn +4sin tr_ ""'," + jcos, cos- ,r cos. J .d1 _ sin" x + 4sin' x.cos' r-sin2 x+3cosa x =fr COS. J x + (3sin2 x.cos' r + 3cosa x) + (sin, x.cos, sina x+3cos2 x-sina x 2,EC BPT dring vdi mgi x thi dk li: m+l>0 L'= m2 -2(* + l) < 0 (rn > -l ft-J: <m<t+",6 V$y l*.',6 <m<t+",6 0,25 0,15 0,25 0,25 0,25 0,25 {J,25 4,25 0,25 0,25 . +zz + z +zg > Jl J3 x' +2y2 + J^ y- +lz Ddu bdng xAy ra khi u5 r1",1L 111 u: 6 : .l .) , sin';r , sin2x A=stn +4sin tr_ ""'," + jcos, cos-. " h, ciu vI( r.o tri6nr). qb - 7 __- * ;i = f il[Vtt'i]T]-r$:' thuc satr kh6ng php thu6c x : A:sin2 xtan2 x+ 4sin2 x- tan2 x +3cos2 x Tim m ae u6t