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