问题过双曲线x2/a2-y2/b2=1的右焦点的直线z被曲线截得的弦长为d,则这样的直线l有多少条?设过右焦点F(c,0)的直线z的方程为y=k(x-c)(为便于研究,l⊥x轴时,认为k→∞),将其代入x2/a2=y2/b2=1并化简得:(b2-a2k2)x2+2a2k2cx-a2c2k2-a2b2=0(*),设直线l与双曲线交于两点A(x1,y1),B(x2,y2),由韦达 If the chord length of the line z of the right focus of the problem hyperbolic curve x2/a2 - y2/b2 = 1 is d, how many lines such a line l have? The line that has passed the right focus F(c, 0) The equation of z is y=k(xc) (For convenience of study, when l⊥x axis, consider k→∞), substitute it into x2/a2=y2/b2=1 and simplify: (b2-a2k2)x2 +2a2k2cx-a2c2k2-a2b2=0(*), set line l and hyperbola at two points A(x1,y1), B(x2,y2), by Veda