Question

高一数学解答 !急!三角函数sin25π/12·cos11π/6-cos11π/12·sin5π/6 的值是A -√2/

Answer 1

（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,