Question

这道题怎么做？求助大神！谢谢！

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A modern hospital is one of those institutions responsible for providing health care to the sick and injured, but it is probably the most familiar 1 everyone and certainly the most complex in its organization. It 2 resembles the earlier institutions that were also 3 as hospitals. Advances in medical science 4 created a revolution in 5 field of health services. The quality of care available to patients has improved; the need for personnel trained in the 6 professions had grown and the variety of ways for people to work with the 7 and injured has increased. Years ago, an individual 8 wanted to enter the health profession had only the choice of becoming a doctor, a dentist, or a hospital administrator. 9 , today, he or she can choose from hundreds of health-related 10 .
1. A. with B. to C. for D. by
2. A. hard B. usually C. hardly D. usual
3. A. know B. knew C. known D. knows
4. A. have B. had C. did D. do
5. A. a B. an C. the D. /
6. A. teaching B. public C. private D. health
7. A. sick B. hospital C. health D. people
8. A. whom B. when C. what D. who
9. A. So B. Yet C. And D. If
10. A. professions B. work C. centers D. colleges

Answer 1

微风迎春

来自科学教育类芝麻团 2017-09-21

1)由正玄定理可得
a：sinA=b:sinB=c:sinC
所以有a+b=c/sinC*sinA+c/sinC*sinB=c/sinC*(sinA+sinB)
（a+b）/（sinA+sinB）=c/sinC=2/sin60=4*3^0.5/3
2)由余弦定理可得到
c^2=a^2+b^2-2a*bcosC
a+b=a*b
带入得到：c^2=(a+b)^2-2a*b-2a*bcosC=(a+b)^2-3(a+b)
即（a+b）^2-3*(a+b）-4=0
解出a+b=4或a+b=-1（舍去）
a+b=a*b=4
a，b就是方程X^2-4X+4=0的两个根
解出a=2，b=2
所以三角形为等边三角形。
其面积为1/2*2*2*sinC=3^0.5

Answer 2

BBCBC
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