6个回答
展开全部
分子 分母 同时竖御乘以 cos10°
sin10°×sin50°×sin70°
= sin10°×sin50°×sin70°× cos10°/余碧岩cos10°
= sin10°× cos10°×sin50°×sin70°/cos10°
= (1/2) × sin20°× sin50°× sin70°/cos10°
= (1/2) × sin20°× sin50°× cos20°/cos10°
= (1/4) × sin40°× sin50°/cos10°
= (1/4) × sin40°× cos40°/慧桐cos10°
= (1/8) × sin80°/cos10°
= (1/8) × sin80°/sin80°
= 1/8
sin10°×sin50°×sin70°
= sin10°×sin50°×sin70°× cos10°/余碧岩cos10°
= sin10°× cos10°×sin50°×sin70°/cos10°
= (1/2) × sin20°× sin50°× sin70°/cos10°
= (1/2) × sin20°× sin50°× cos20°/cos10°
= (1/4) × sin40°× sin50°/cos10°
= (1/4) × sin40°× cos40°/慧桐cos10°
= (1/8) × sin80°/cos10°
= (1/8) × sin80°/sin80°
= 1/8
已赞过
已踩过<
评论
收起
你对这个回答的评价是?
2018-12-22 · 知道合伙人教育行家
关注
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