求值cos9π/4+tan(-11π/6)-sin9π/4+tan(--11π/3)

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求值cos9π/4+tan(-11π/6)-sin9π/4+tan(--11π/3)

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

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