高一数学解答 !急!三角函数sin25π/12·cos11π/6-cos11π/12·sin5π/6 的值是A -√2/2 B √2/2 C -sinπ/12 D sinπ/12 详细解答!求
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高一数学解答 !急!三角函数sin25π/12·cos11π/6-cos11π/12·sin5π/6 的值是A -√2/2 B √2/2 C -sinπ/12 D sinπ/12 详细解答!求
高一数学解答 !急!三角函数
sin25π/12·cos11π/6-cos11π/12·sin5π/6 的值是
A -√2/2 B √2/2 C -sinπ/12 D sinπ/12
详细解答!求
高一数学解答 !急!三角函数sin25π/12·cos11π/6-cos11π/12·sin5π/6 的值是A -√2/2 B √2/2 C -sinπ/12 D sinπ/12 详细解答!求
(sin25π/12*cos11π/6)-(cos11π/12*sin5π6)
=(sinπ/12*cosπ/6)-(-cosπ/12*sinπ/6)
=sinπ/12*cosπ/6+cosπ/12*sinπ/6
=sin(π/12+π/6)
=sin(π/4)
=√2/2
答案是B
啊啊啊,
根据三角函数以及角度换算之间的关系,选 B.
sin25π/12·cos11π/6-cos11π/12·sin5π/6
=-sinπ/12·cos5π/6+cosπ/12·sin5π/6
=sin(5π/6-π/12)
=sin3π/4
=√2/2
选B
sin25π/12·cos11π/6-cos11π/12·sin5π/6
=sinπ/12·cosπ/6+cosπ/12·sinπ/6
=sin(π/6+π/12)
=sinπ/4
=√2/2
选B
B
原式=sinπ/12·cosπ/6+cosπ/12·sinπ/6
=sin(π/12+π/6)=sin(π/4)=√2/2