There is a point P on the hyperbola x ^ 2 / A ^ 2-y ^ 2 / b ^ 2 = 1, F1F2 is the left and right focus of the hyperbola, the angle f1pf2 = 90 ° and the three sides of the triangle f1pf2 The eccentricity of hyperbola can be determined by the arithmetic sequence

There is a point P on the hyperbola x ^ 2 / A ^ 2-y ^ 2 / b ^ 2 = 1, F1F2 is the left and right focus of the hyperbola, the angle f1pf2 = 90 ° and the three sides of the triangle f1pf2 The eccentricity of hyperbola can be determined by the arithmetic sequence

So 2pf1 = PF2 + F1F2 and pf1-pf2 = 2A, Pf1 + (pf1-pf2) = f1f2pf1 + 2A = 2cpf1 = 2c-2apf2 = pf1-2a = 2c-4af1f2 ^ 2 = Pf1 ^ 2 + PF2 ^ 24C ^ 2 = 4C ^ 2-8ac + 4A ^ 2 + 4C ^ 2-16ac +