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11.:a0ax2+bx+c=0abcab,c.2.:.3.:ax2+bx+c=0(a0)=b2-4ac.0==0=0=0=.4.ax2+bx+c=0(a0)0.acxxabxx)2(a2ac4bbx)1(212122,15.12(0)xaaxa2()(0)xabbxab2()(0)axbccaxbc22()()()axbcxdac()axbcxd220(,0)()0axbxabxaxb0290(3)(3)0xxx230(3)0xxxx3(21)5(21)0(35)(21)0xxxxx22694(3)4xxx2241290(23)0xxx24120(6)(2)0xxxx225120(23)(4)0xxxx3122220()()022PPxPxqxq22233310()()1022xxx122220(0)()0()()022bbbaxbxcaaxxcaxacaaa2222224()()2424bbbbacaxcxaaaa22221111210(4)10(2)2102222xxxxx420(0)axbxca2224()24bbacxaa240bac21,242bbacxa240bac1,22bxa240bac20(0)axbxcaabc24bac21,242bbacxa5ax2+bx+c=0(a0)(acxxabxx2121=b2-4ac)1ab=00b=002ac=10a=c03ac=0ab0c=0b04ac=0ab=0c=0b=05ac=0c=06ac0ac7ac0ab0acab8ac0ab0acab9ac0ab00acab010ac0ab00acab0.60.3ax2+bx+c=a(x-x1)(x-x2)ax2+bx+c=a2ac4bbxa2ac4bbxa22.7x2-x1+x2x+x1x2=0..8--------x(1)a,a(1+x),a(1+x)2.2=++=.9.0)1(.0.210..0)3(0)2(0)4(0)1(0)4(0)2(0)3(0)1(0)4)(3(0)2)(1()3(;02;111)xx(xx4)xx()xx()xx(xx4)xx()xx(xx2)x1x(x1x2)x1x(x1xxx4)xx()xx(xx2)xx(xx)1(212122122121212212212122222221221221212212221222121212()2xxxxxx12121211xxxxxx22121212()()4xxxxxx2121212||()4xxxxxx2212121212()xxxxxxxx22111212121222212()4xxxxxxxxxxxxxx4xx.22xx2xx.12xx)2(221212121.,)2(34xx34xx)1()916xx(34xx)3(2121222121.0x,0x:.1xxBsinAcos,1AcosAsin,90BABsinx,Asinx)4(21222122214.0x,0x:.x,x),,(,x,x)5(212121.k,)6(.,;,)7(1.a02.a0a0a000a=0,b=0a=0,b=0a=0,b=0.1a0aaa-a,2aa531aaa02=.23aa0x+y49a^2x+y^2x^2+2xy+y^231.ab=aba0b02.ab=aba0b03.ab=aba0b04.,123162345I.II.1.2.1abca2+b2c21ABC90C22cab22bca22acb232abca2+b2c21c2c2a2+b2c2a2+b2ABCCc2a2+b2ABCCc2a2+b2ABCabc222abcabc222acbabcb34574EFGHSSSABCD2214()2abbac221422Sabcabc222()2Sabaabb222abc1()()2Sabab2112S222ADEABESSabc6222abcabcabc3,4,56,8,105,12,137,24,25n221,2,1nnn2,nn2221,22,221nnnnnn2222,2,mnmnmn,mnmn1234.abca2+b2c2?5.?1ABCD.54321cbaHGFEDCBAabccbaEDCBAbacbaccabcabABDOC8CDABABCDO2..3.ABCD.3;2;1(4)4(1)(2)(3)(4)ABCD.5.ABCD.3216.321ABCD.7.ABCD.3218.321ABCD.S=ah(ahABDOCADBCADBCOCDBAOCDBAO9)S=ab(ab)S=ah(ah)(bc)(a)(b)12=34x1x2,xn10T=5x1x2,xnS2=S2