sin10°×sin50°×sin70°等于多少

来源：学生作业帮助网编辑：作业帮时间：2024/04/27 17:48:12

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

求值sin10°sin30°sin50°sin70° sin10°sin30°sin50°sin70°=? sin10°sin30°sin50°sin70°=? sin10°*sin30°*sin50°*sin70° 怎么做? sin10°sin30°sin50°sin70°=? sin10°*sin30°*sin50°*sin70°等于多少? 求值：sin10°sin50°sin70°sin80° 化简：sin10°sin50°sin60°sin70° sin10°×sin50°×sin70°等于多少 sin10°*sin50°*sin70°等于好多求值：sin10°sin50°·sin70° sin10°sin50°sin70° 怎样化简求值? 4×sin10°×sin50°×sin70°怎么化简 sin10°sin50°-sin50°sin70°-sin70°sin10°=?请给出过程,谢谢了谢谢! 求cos20°cos40°cos80°sin10°sin50°sin70° 高一数学题：sin10°sin30°sin50°sin70°=? 试比较sin10°,sin50°,sin30°,sin70°的大小 sin70°cos20°-sin10°sin50°的值是多少?,麻烦给出过程