在平面直角坐标系xoy中，椭圆C：
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椭圆C：
+x2 25
=1的左、右焦点分别为F1（-4，0）、F2（4，0），y2 9
设P（x1，y1），由已知PF1⊥PF2，所以
•PF1
=0，PF2
即 （-4-x1，-y1）•（4-x1，-y1）=0，
∴x12+y12=16，
又因为
+x12 25
=1，y 22 9
解得 y1=±
，所以，△PF1F2的面积S=9 4
×2c•|y1|=9．1 2
故答案为：9．
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| I was fifteen months old, a happy kid until the day I fell.It was a__1__fall.I landed on a glass rabbit which cut my eye badly enough to make it blind.Trying to save the eye, the doctors stitched (缝合) the eyeball together where it was__2__, leaving a big ugly scar (疤痕) in the middle of my eye.The attempt __3__, but my mother, in all of her wisdom  , found another doctor who knew that if the eye wereremoved__4__, my face would grow up badly distorted (扭曲), __5__my scarred, sightless, cloudy and gray  eye lived on with me.As I grew, this sightless eye in so many ways__6__me.I walked with my face looking at the__7__so that people would not see the__8__me.Yet my mother would say to me, at every turn, "Hold your head up high and__9__the world.If you hold your head up high, it will be OK, and people will see your__10__soul." She continued this__11__wheneve  r I wastrying to hide. Mama's words were of great help for me to face the world__12__.As a teenager, even though I tended to look down to hide my shame, I found that sometime when I held my head up high and let people know me, they__13__me.In high school, I was_  _14__both academically and socially.I was__15__elected class president.My mother's words helped me begin to realize that by letting people look at my face, I let them__16__the intelligence and beauty behind both eyes, even if they couldn't see it on the__17__. Now I'm a happy wife and great mother.The message "Hold your head up high" has been__18__ many times in my__19__home.Each of my children has felt__20__invitation, and the gift my mother gave me has lived on in another generation. | ||||
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