焦点坐标为(1/2,0).设直线方程为y=k(x-1/2),代入抛物线方程得,
k2x2-(k2+2)x+k2/4=0.由韦达定理x1+x2=1+2/k2,x1*x2=1/4.
根号绝对值(x1x2-y1y2)=根号绝对值(1/4-根号2x1*根号2x2)=根号绝对值(1/4-1)=根号(3/4)
焦点坐标为(1/2,0).设直线方程为y=k(x-1/2),代入抛物线方程得,
k2x2-(k2+2)x+k2/4=0.由韦达定理x1+x2=1+2/k2,x1*x2=1/4.
根号绝对值(x1x2-y1y2)=根号绝对值(1/4-根号2x1*根号2x2)=根号绝对值(1/4-1)=根号(3/4)