A
解析分析:設(shè)AB的斜率為k′,A(x1,y1)B(x2,y2),中點(diǎn)坐標(biāo)(x0,y0)把A,B代入雙曲線方程兩式想減整理可得
=
′,根據(jù)AB的中點(diǎn)在直線y=kx上,代入得y0=kx0,進(jìn)而求得k和k′的關(guān)系.
解答:設(shè)AB的斜率為k′,則A(x1,y1)B(x2,y2),中點(diǎn)坐標(biāo)(x0,y0)x0=
,y0=
由題意:2x12-3y12=6,2x22-3y22=6兩式相減,整理得2(x1+x2)(x1-x2)=3(y1+y2)(y1-y2)∴
=
即
=
′∵AB的中點(diǎn)在直線y=kx上,代入得y0=kx0,∴
=k∴k′=
故選A
點(diǎn)評(píng):本題主要考查了直線與圓錐曲線的綜合問(wèn)題.涉及了直線的斜率問(wèn)題,直線方程問(wèn)題,考查了學(xué)生對(duì)所學(xué)知識(shí)綜合性的把握.