设(x1,y1),(x2,y2)是弦的端点,则x1²/16+y1²/4=1x2²/16+y2²/4=1两个方程相减得:(x1+x2)(x1-x2)/16+(y1+y2)(y1-y2)/4=0∵(1,1)是中点,∴x1+x2=2y1+y2=2代人上式得:2(x1-x2)/16+2(y1-y2)/4=0解得:(y1-y2)/(x1-x2)=-1/4∴弦所在的直线方程是:y-1=(-1/4)(x-1),即:x+4y-5=0