A point P on the hyperbola X & # 178; - Y & # 178 / 9 = 1 with F2 as the left and right focus satisfies the vector Pf1 * vector PF2 = 0 |Vector Pf1 | + | vector PF2 | =? Seek the concrete process

A point P on the hyperbola X & # 178; - Y & # 178 / 9 = 1 with F2 as the left and right focus satisfies the vector Pf1 * vector PF2 = 0 |Vector Pf1 | + | vector PF2 | =? Seek the concrete process

According to the definition of hyperbola, pf1-pf2 = 2A, ① ∵ Pf1 · PF2 = 0 ∵ Pf1 & # 178; + PF2 & # 178; = (2C) &# 178; & nbsp; & nbsp; ② ∵ Pf1 + PF2 & # 178; = (pf1-pf2) &# 178; + 4pf1 × PF2 & nbsp; ③ & nbsp; & nbsp; & nbsp; (pf1-pf2) &# 178; = Pf1 & # 178; + PF2 & # 178; - 2pf1 ×