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F1和F2是椭圆x^2/25+y^2/9=1的两个焦点,AB是经过F1的弦,若弦/AB/=8则/F2A/+/F2B/=
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F1和F2是椭圆x^2/25+y^2/9=1的两个焦点,AB是经过F1的弦,若弦/AB/=8则/F2A/+/F2B/=
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a=5,b=3,/F1A/+/F2A/=/F1B/+/F2B/=2a=10,所以/F2A/+/F2B/+/AB/=/F1A/+/F1B/+/F2A/+/F2B/=20,/AB/=8,所以/F2A/+/F2B/=12.
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