sin10,sin20,cos10,cos20分别为多少(sin30/sin10)-(cos30/cos10)=?[根号(1-2sin20 cos20)]/(sin20-cos20)
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sin10,sin20,cos10,cos20分别为多少(sin30/sin10)-(cos30/cos10)=?[根号(1-2sin20 cos20)]/(sin20-cos20)
sin10,sin20,cos10,cos20分别为多少
(sin30/sin10)-(cos30/cos10)=?
[根号(1-2sin20 cos20)]/(sin20-cos20)
sin10,sin20,cos10,cos20分别为多少(sin30/sin10)-(cos30/cos10)=?[根号(1-2sin20 cos20)]/(sin20-cos20)
题目1是:(sin30/sin10)-(cos30/cos10)
= (sin30cos10-cos20sin10)/(sin10cos10)
= sin(30-10)/(1/2sin20)
=2
题目2是:[根号(1-2sin20 cos20)]/(sin20-cos20)
= (cos20-sin20)/(sin20-cos20)
= -1
你把原题贴出来吧,估计你的题目可以直接化简的
可以化简的 答案是2
(sin30cos10-cos30sin10)/(sin10cos10)
=2sin20/2sin10cos10
=2
(sin30/sin10)-(cos30/cos10)= (sin30cos10-cos30sin10)/sin10cos10
(sin30cos10-cos30sin10)=sin(30-10)
2sin10cos10=sin(2*10)'这两个公式很重要
(sin30/sin10)-(cos30/cos10)=sin20/(1/2*sin20)=2
用计算器算