y=1/X在点（2,1/2)处的切线方程为x+4y-4=0y=1/X在点（2,1/2)处的法线方程为4x-y-15/2=0析：y的导数 =-1/x^2,则在点（2,1/2)处的切线斜率为-1/4则y=1/X在点（2,1/2)处的切线方程为y-1/2=(-1/4)(x-2)整理即得x+4y-4=0...