已知抛物線y^2=4x,點P(1,2),A(x1,y1),B(x2,y2)在抛物線上,當PA與PB的斜率存在且傾斜角互補時,求. 求Y1+Y2的值及直線AB的斜率

已知抛物線y^2=4x,點P(1,2),A(x1,y1),B(x2,y2)在抛物線上,當PA與PB的斜率存在且傾斜角互補時,求. 求Y1+Y2的值及直線AB的斜率

(1)kPA=y1-2/x1-1=y1-2/(y1^2/4-1)=4(y1-2)/(y1^2-4)=4/(y1+2)kPB=y2-2/x2-1=y2-2/(y2^2/4-1)=4(y2-2)/(y2^2-4)=4/(y2+2)當PA與PB的斜率存在且傾斜角互補時,kPA+kPB=0 4/(y2+2)+4/(y1+2)=0 4(y1+2+y2+2)/(y1+2)(y2+2…