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来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 02:35:35
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一道填空题,填空题是第八题 http://hi.baidu.com/%C4%E3tm%B1%F0%D5%D2pia/album/item/2270c427f2655cee4623e882.htmlhttp://hi.baidu.com/%C4%E3tm%B1%F0%D5%D2pia/album/item/2270c427f2655cee4623e882.html#IMG=6d552e4124d66606510ffe81http://hi.baidu
1.延长AB,交点为D
所以 CD = 7cos 15,BD = 7sin 15
角ACD = 50度
AD = CDtan50 = 7cos15tan50
所以 AB = AD - BD = 7cos15tan50- 7sin 15
2.填空
BC = ABcot a
BD = ABcot b
s = BC - BD = AB(cot a - cot b)
AB = s/(cot a - cot b)
3.AC = 35*40 = 1440
过C做垂线CH
CH = 1440sin 75,AH = 1440cos 75
BH = CH cot 30
AB = BH - AH,自己算去.
过P做AB垂线PM
所以 BM = PMcot 30,AM = PMcot 45 = PM
AB = BM + AM = PMcot 30 + PM
自己算吧