a，b，c为△ABC的三边，其面积S△ABC=123，bc=48，b-c=2，求_爱下问搜题

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问题解答题

a，b，c为△ABC的三边，其面积S_△ABC=12

3

，bc=48，b-c=2，求a．

答案

由S_△ABC=

1

2

bcsinA，

得12

3

=

1

2

×48sinA，

∴sinA=

3

2

．

∴A=60°或A=120°．

由bc=48，b-c=2得，b=8，c=6．

当A=60°时，a²=8²+6²-2×8×6×

1

2

=52，

∴a=2

13

．

当A=120°时，a²=8²+6²-2×8×6×（-

1

2

）=148，

∴a=2

37

．

单项选择题

急性乳腺炎形成脓肿后治疗是

A．加大抗生素用量

B．局部理疗

C．全身营养支持

D．及早切开引流

E．患乳停止哺乳

完形填空

A man and his family were in Europe. Once they needed to drive 3 days   36, day and night, to get to Germany. His little daughter had never 37 at night without a break before. She was 38  the first night in the car, with terrible deep darkness outside.
“Where are we going, Daddy?” asked the daughter. “To your uncle’s house in Germany.” Father answered.
“Have you been to his    39  before?” “No.”
“Then, do you know the   40 ?” “Maybe, we can read the map.”
Short pause. “Do you know how to read the map?” “Yes, we will get there 41    . Don’t worry.”
The same dialogue 42  a few times within the first night, and also the second night.   43  on the third night, his daughter was quiet. Father thought that she might have fallen   44 , but when he looked into the mirror, he saw that she was awake and was just   45 calmly. He couldn’t help wondering   46 she was not asking the questions anymore.
“Dear, do you know where we are going?” “Germany, uncle’s house.”
“ Do you know how we are getting there?” “No.”
“ Then why aren’t you asking anymore?” “Because Daddy is   47 .”
Because Daddy is driving. This answer from a 3 years old girl has then become the   48  and help this man for many years whenever he has questions and
49 on his journey. We may 50 the destination and sometimes we may just know it 51 the little girl-“Germany”, without understanding where or what it 52 is. We do not know the way. We do not know how to read the map. We do not know if we can find   53 along the way to eat in. But the little girl knows the most 54 thing-Daddy is driving-and so she is safe and secure. She knows that her Daddy will 55  all that she needs.

A．occasionally

D．continuously

B．dangerously

A．looking around

B．coming about

C．getting through

B．achievements

D．restaurants