问题
选择题
双曲线
（ ）
|
答案
∵直线PF1，PF2倾斜角之差为
，π 3
∴∠F1PF2=
，π 3
∴△PF1F2面积=16×cot
=16π 6
．3
故选A．
搜题请搜索小程序“爱下问搜题”
双曲线
（ ）
|
∵直线PF1，PF2倾斜角之差为
，π 3
∴∠F1PF2=
，π 3
∴△PF1F2面积=16×cot
=16π 6
．3
故选A．
| Choose the different pronunciation of the underlined letters. 选择单词中划线字母发音不同的一个。 |
| ( ) 1. A. talk ( ) 2. A. home ( ) 3. A. surprise ( ) 4. A. phone ( ) 5. A. sugar ( ) 6. A. found ( ) 7. A. cheap ( ) 8. A. down ( ) 9. A. what ( ) l0. A. walked | B. many B. have B. cookie B. hello B. mum B. about B. child B. tomorrow B. who B. wanted | C. walk C. like C. arrive C. come C. but C. couch C. christmas C. know C. where C. liked | D. ball D. he D. like D. okay D. bus D. should D. couch D. throw D. when D. laughed |