求值:1.cos(-14π/3) 2.tan(35π/6) 3.sin(-25π/6)1·cos(-14π/3) 2·tan(35π/6)3.sin(-25π/6)

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求值:1.cos(-14π/3) 2.tan(35π/6) 3.sin(-25π/6)1·cos(-14π/3) 2·tan(35π/6)3.sin(-25π/6)
求值:1.cos(-14π/3) 2.tan(35π/6) 3.sin(-25π/6)
1·cos(-14π/3) 2·tan(35π/6)3.sin(-25π/6)

求值:1.cos(-14π/3) 2.tan(35π/6) 3.sin(-25π/6)1·cos(-14π/3) 2·tan(35π/6)3.sin(-25π/6)

cos(-14π/3)=cos(4π+2π/3)=-1/2

 tan(35π/6)=tan(6π-π/6)=-tanπ/6=-√3/3

sin(-25π/6)=sin(-4π-π/6)=-sinπ/6=-1/2