sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)

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sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)sin(-11π/6)+cos12π/5·tan3π+c

sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)
sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)

sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)
解sin(-11π/6)=sin(2π-11π/6)=sinπ/6=1/2
cos12π/5·tan3π=cos12π/5×tanπ=cos12π/5×0=0
cos(-π/4)=cos(π/4)=√2/2故sin(-11π/6)+cos12π/5·tan3π+cos(-π/4)
=1/2+0+√2/2
=(√2+1)/2