谁来帮帮我啊？ 30乘以sin15度的积再除以二分之根号三等于多少？

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sin15°=根号[(1-cos30°)/2]=根号搜蔽消[(2-根号3)/4]=1/2(根号3-1)/根号2

30sin15°/并衡[(根号3)/2
=30*1/2*(根号3-1)/世知跟号2*2/根号3
=30(根号3-1)/根号6
=30/根号2-30/根号6
=15根号2-5根号6

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30×sin15^o/二分之根号三友码锋 =20×根号好晌三 sin15^o

=20×根号三(sin(45-30)^o)

=20×根号三(四分之根号六 - 四分之模虚根号二 )

=15根号二 -5根号六

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