神马作文网sin10°×sin50°×sin70°等于多少
来源：学生作业帮 编辑：神马作文网作业帮 分类：数学作业 时间：2024/11/23 16:55:31
sin10°×sin50°×sin70°等于多少
分子 分母 同时乘以 cos10°
sin10°×sin50°×sin70°
= sin10°×sin50°×sin70°× cos10°/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°/cos10°
= (1/8) × sin80°/cos10°
= (1/8) × sin80°/sin80°
= 1/8
sin10°×sin50°×sin70°
= sin10°×sin50°×sin70°× cos10°/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°/cos10°
= (1/8) × sin80°/cos10°
= (1/8) × sin80°/sin80°
= 1/8
sin10°×sin50°×sin70°等于多少
sin10°*sin50°*sin70°等于好多
sin10°sin50°-sin50°sin70°-sin70°sin10°=?
sin10°sin30°sin50°sin70°=?
求值：sin10°sin50°sin70°sin80°
求值：sin10°sin50°·sin70°
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