}1,2,1{s1}2,1,1{s2|s||s|/sscos212121.3),1,2,4()2,3,1(),1,2,4()10,1,2()1,2,2(00yxn11222200yx.2,1000zyx}3,2,1{τ200tt103410nτ0200ttt310t22yxyxf22yxxyf.igrad)1,0(f)1,1,1(n.2zyx.4c)ba(2)ac()]cb()ba[(.22516946d}.1,1,1{n.043zyx}.1,3,1{}1,1,2{}1,0,1{n.023zyx}2,1,4{n}2,3,6{n}.3,2,2{n.3,2,051.1222yzx.2,2,192.2.33.32411341354141414)6(lu.1.0,02ayxazayax0)1()1(:1zCByxA,0,02CBACBA.0123zyx,0123,012zyxzyx).1(21,2yzyx2222)1(414yyzxL0)2(72yxzx0722)1(zyx),,(000zyx【解】过直线的平面束方程为即设切点为0722)1(213232221000202020000zyxzyxzyx)2,0,3(:,32,0M)2,0,3(72zx)2,2,1(2164zyx则点处切平面;点处切平面.或(1,2,2))2,3,1()2,1,1()1,1,1(21nn032012zyxzyx【解】过直线的平面束方程为0)32(12zyxzyx031)21()2()1(zyx即0)21(2)2(3)1(25.0171293zyxj)2(i)2(),(grad0000),(00yxxyyxhyx.855)2()2(),(00202020020000yxyxyxxyyxg)75(855),,(2222xyyxxyyxyxL,),(),(2yxgyxf.075,0)2(8100)2(81022xyyxLxyxyLxyyxLxyx),5,5(),5,5(21MM).35,35(),35,35(43MM450)()(21MfMf.150)()(41MfMfjyzixzgradz361619,361614,//},{2222yxyyxxyzxzdydx,94ydyxdx94Cxy3,1yx3C)11,3,1(P94223361614xyyxz