知识问答
最佳答案:(1)x=arcsin(2/5) ,(x属於[-π/2,π/2])(2)x=arcsin(-1/3) ,(x属於[-π/2,π/2])(3)x=arcsin(0
最佳答案:两角和公式sin(a+b)=sinacosb+cosasinbsin(a-b)=sinacosb-sinbcosa cos(a+b)=cosacosb-sin