261yax2yax2ya(xh)2k1yax221yax2(a0)x(1)m(2)m?xy?(3)m??xyxyax2bxc(a0)a0bc0bc0yax2(a0)(00)yx0(1)x2m42m20m2m42m20m2m3m(2)m20(3)m20m__________x_____0yxx_____0yx2y3x26x8y3x2(1)yax2bxca(x2(2)(3)(1)y2bxc23y22x1bc(2)y24x53ABxA(20)yax2BCB(11)(1)(2)DAODOBCD(1)ABA(20)B(11)ykxbkbyax2B(11)ayx2y2(2)yx2y2C(24)SOBCABCOAB3SAODOBCOA2DDy223xD(3)(3)yax2(a0)y2x3A(1b)(1)ab(2)yax2(3)xyax2yx(4)y2121y(m1)x2m22m3m______2y3x2ykx3(2b)k______b______3y(x1)22yx2________________________4yx2xya(xh)2ky____________________________________1y(mn)x2mxn()Amnm0BmnmC.mnn0D.mn2ymx1y2x28xk8(34)mk()ABC.D.3ab0yax2yaxb()1(1)a(2)a2yx2yax1(1)a(2)A(x1y1)B(x2y2)PABPaP(3)ABd|x1x2|ad(4)C(01)lxlAB