已知抛物线y^2=4x,点P(1,2),A(x1,y1),B(x2,y2)在抛物线上,当PA与PB的斜率存在且倾斜角互补时,求.求Y1+Y2的值及直线AB的斜率

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已知抛物线y^2=4x,点P(1,2),A(x1,y1),B(x2,y2)在抛物线上,当PA与PB的斜率存在且倾斜角互补时,求.
求Y1+Y2的值及直线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)当PA与PB的斜率存在且倾斜角互补时,kPA+kPB=0 4/(y2+2)+4/(y1+2)=0 4(y1+2+y2+2)/(y1+2)(y2+2...