在锐角△ABC中,a、b、c分别为角A、B、C所对的边,且根号3*a=2c*sinA
在锐角△ABC中,a、b、c分别为角A、B、C所对的边,且根号3*a=2c*sinA(1)确定角C的大小(2)若c=根号7,且△ABC的面积为(3根号3)/2,求a+b的...
在锐角△ABC中,a、b、c分别为角A、B、C所对的边,且根号3*a=2c*sinA
(1)确定角C的大小
(2)若c=根号7,且△ABC的面积为(3根号3)/2,求a+b的值 展开
(1)确定角C的大小
(2)若c=根号7,且△ABC的面积为(3根号3)/2,求a+b的值 展开
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对于任意三角形ABC,都有 a/sinA=b/sinB=c/sinC=2R ,你的题打错了。
参考资料: http://baike.baidu.com/view/147231.htm?fr=ala0_1_1
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用正弦定理 给出的等式两边a&c换成sinA,sinC .解得SINC等于三分之二
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2010-06-26
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(1): ∵ 根号3*a=2c*sinA=2a*sinC
∴ sinC=(根号3)/2
∵△ABC为锐角三角形
∴C=60°
(2): ∵S△ABC=(1/2)ab*sinC=(3根号3)/2
∴a*b=6
∵cosC=(a^2+b^2-c^2)/(2ab)=1/2
∴a^2+b^2=13
∴a+b=根号((a+b)^2)=根号(a^2+b^2+2ab)=根号(13+2+6)=5
∴ sinC=(根号3)/2
∵△ABC为锐角三角形
∴C=60°
(2): ∵S△ABC=(1/2)ab*sinC=(3根号3)/2
∴a*b=6
∵cosC=(a^2+b^2-c^2)/(2ab)=1/2
∴a^2+b^2=13
∴a+b=根号((a+b)^2)=根号(a^2+b^2+2ab)=根号(13+2+6)=5
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According to the British Ministry of Defense website, Ainsworth said the decision was heard in Afghanistan,coach handbags, the views of the British generals made.
Ainsworth said: "Although in recent weeks, the mortality rate of British troops in Afghanistan has increased, but in order to ensure
We are now consolidating the operations process and we have already achieved, it is necessary to send more troops. "
British commander in Afghanistan said that this decision will help to maintain the current British operations in Afghanistan effectiveness,chanel handbags, especially in the next month during the presidential election in Afghanistan.
This month, there have been 19 British soldiers killed in Afghanistan. According to the British Ministry of Defense published on the website, since the war in Afghanistan, a total of 188 British soldiers were killed.
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