求值cos9π/4+tan(-11π/6)-sin9π/4+tan(--11π/3)
问题描述:
求值cos9π/4+tan(-11π/6)-sin9π/4+tan(--11π/3)
答
cos9π/4+tan(-11π/6)-sin9π/4+tan(--11π/3)
=cos(2π+π/4)+tan(-2π+π/6)-sin(2π+π/4)+tan(-4π+π/3)
=cosπ/4+tanπ/6-sinπ/4+tanπ/3
=√2/2+√3/3-√2/2+√3
=4√3/3