Cho Elip \((E): \, \,{{{x^2}} \over {25}} + {{{y^2}} \over 4} = 1 \). Tọa độ điểm \(M \in (E) \) sao cho \( \widehat {{F_1}M{F_2}} = {90^0} \) là:
A.\({M_1}\left( {{{5\sqrt {357} } \over {21}};{{4\sqrt {21} } \over {21}}} \right);{M_2}\left( {{{5\sqrt {357} } \over {21}}; - {{4\sqrt {21} } \over {21}}} \right);{M_3}\left( { - {{5\sqrt {357} } \over {21}};{{4\sqrt {21} } \over {21}}} \right);{M_4}\left( { - {{5\sqrt {357} } \over {21}}; - {{4\sqrt {21} } \over {21}}} \right)\).
B.\({M_1}\left( {{4 \over {21}};{5 \over {21}}} \right);{M_2}\left( { - {4 \over {21}};{5 \over {21}}} \right);{M_3}\left( {{4 \over {21}}; - {5 \over {21}}} \right);{M_4}\left( { - {4 \over {21}}; - {5 \over {21}}} \right)\).
C.\({M_1}\left( {{{5\sqrt {357} } \over {21}};1} \right);{M_2}\left( {{{5\sqrt {357} } \over {21}}; - 1} \right);{M_3}\left( { - {{5\sqrt {357} } \over {21}};1} \right);{M_4}\left( { - {{5\sqrt {357} } \over {21}}; - 1} \right)\).
D.\({M_1}\left( {{4 \over {21}};1} \right);{M_2}\left( { - {4 \over {21}};1} \right);{M_3}\left( {{4 \over {21}}; - 1} \right);{M_4}\left( { - {4 \over {21}}; - 1} \right)\).