计算:sin(π/12)sin(5π/12)
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计算:sin(π/12)sin(5π/12)
要用二倍角与半角的公式
要用二倍角与半角的公式
![计算:sin(π/12)sin(5π/12)](/uploads/image/z/19029906-18-6.jpg?t=%E8%AE%A1%E7%AE%97%3Asin%28%CF%80%2F12%29sin%285%CF%80%2F12%29)
sin(π/12)sin(5π/12)
=-1/2[cos(π/12+5π/12)-cos(π/12-5π/12)]
=-1/2(cosπ/2-cosπ/3)
=-1/2(0-1/2)
=1/4
=-1/2[cos(π/12+5π/12)-cos(π/12-5π/12)]
=-1/2(cosπ/2-cosπ/3)
=-1/2(0-1/2)
=1/4
计算:sinπ12
计算cosπ/12*sinπ/12
已知sin(π+α)=-12,计算:
已知sin(π+α)=−12,计算:
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cos*π/12—sin*π/12
cos5π/12=sinπ/12
求值:sin(π/12)+cos(π/12)
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如果sin(π+A)=12