设直线与椭圆交点(x1,y1),(x2,y2),则x1+x2=4,y1+y2=2代入椭圆方程得：x1²/16+y1²/4=1x2²/16+y2²/4=1,两式相减得(1/16)·(x1+x2)(x1-x2)+(1/4)(y1+y2)(y1-y2)=0(x1-x2)/4+(y1-y2)/2=0∴(y1-y2)/(...