这个数学题的解题过程是什么?
4个回答
2021-05-25 · 知道合伙人教育行家
关注
展开全部
既然 ∠C = 90°,sin∠DAC = √3/3 = 1/√3,那么就有:
cos∠DAC = √(1-sin²∠DAC) = √(2/3) = √2/√3
tan∠DAC = CD/AC = sin∠DAC/cos∠DAC = 1/√2
所以,
CD = √2 * AC = √2 * √6 = √12 = 2√3
又因为 CD:DB = 1:3,所以
DB = 3CD, BC = CD + DB = 4CD = 8√3
因此,AB = √(AC²+BC²) = √(6+3*64) = √198 = 3√22
S△DAB = 1/2 * DB * AC = 1/2 * (3 * 2√3) * √6 = 3√18 = 9√2
cos∠DAC = √(1-sin²∠DAC) = √(2/3) = √2/√3
tan∠DAC = CD/AC = sin∠DAC/cos∠DAC = 1/√2
所以,
CD = √2 * AC = √2 * √6 = √12 = 2√3
又因为 CD:DB = 1:3,所以
DB = 3CD, BC = CD + DB = 4CD = 8√3
因此,AB = √(AC²+BC²) = √(6+3*64) = √198 = 3√22
S△DAB = 1/2 * DB * AC = 1/2 * (3 * 2√3) * √6 = 3√18 = 9√2
已赞过
已踩过<
评论
收起
你对这个回答的评价是?
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询