sin10°sin50°-sin50°sin70°-sin70°sin10°=?请给出过程,谢谢了谢谢!

来源：学生作业帮助网 编辑：作业帮 时间：2024/11/14 23:53:58

sin10°sin50°-sin50°sin70°-sin70°sin10°=?请给出过程,谢谢了谢谢!
sin10°sin50°-sin50°sin70°-sin70°sin10°=?
请给出过程,谢谢了谢谢!

sin10°sin50°-sin50°sin70°-sin70°sin10°=?请给出过程,谢谢了谢谢!
=sin10sin50-sin70sin10-sin50sin70
=sin10{sin(60-10)-sin(60+10)}-sin(60-10)sin(60+10)
=sin10(-2sin10*cos60)-sin60*sin60cos10*cos10+sin10*sin10cos60*cos60
=-sin10*sin10-3/4+sin10*sin10
=-3/4

把这三个乘积都用积化和差公式就可以解决

sin20°cos70°+sin10°sin50°等于 求值sin10°sin30°sin50°sin70° sin10°sin30°sin50°sin70°=? sin20°cos70°+sin10°sin50° sin20°cos70°+sin10°sin50° sin20°cos70°+sin10°sin50°等于 cos10°sin40°-sin10°sin50° sin10°sin40°+sin50°cos10° sin10°sin30°sin50°sin70°=? sin10°*sin30°*sin50°*sin70° 怎么做? sin10°sin30°sin50°sin70°=? 2sin50°+2sin10°sin40°/cos10° (sin10°+cos50°)/(cos10°-sin50°)? sin10°*sin30°*sin50°*sin70°等于多少? sin10°cos50°+sin50°cos10° sin10°乘以sin40°+sin50°乘以sin80° sin10°cos50°+sin50°cos10° sin10°乘以sin40°+sin50°乘以80°