Suppose that the foci of the ellipse are and where and

MATHEMATICS · Subjective · CBSE · Mathematics · Conic Sections · Conic Sections

Problem

Suppose that the foci of the ellipse x29+y25=1\frac{x^2}{9} + \frac{y^2}{5} = 1 are (f1,0)(f_1, 0) and (f2,0)(f_2, 0) where f1>0f_1 > 0 and f2>0f_2 > 0 . Let P1P_1 and P2P_2 be two parabolas with a common vertex at (0,0)(0, 0) and with foci at (f1,0)(f_1, 0) and (2f2,0)(2f_2, 0) , respectively. Let T1T_1 be a tangent to P1P_1 which passes through (2f2,0)(2f_2, 0) and T2T_2 be a tangent to P2P_2 which passes through (f1,0)(f_1, 0) . If m1m_1 is the slope of T1T_1 and m2m_2 is the slope of T2T_2 , then the value of (1m12+m22)\left( \frac{1}{m_1^2} + m_2^2 \right) is

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