式子sin10π/3-根号2cos(-19π/4)-1/2tan(-13π/3)的值是
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式子sin10π/3-根号2cos(-19π/4)-1/2tan(-13π/3)的值是
sin(10π/3)-√2cos(-19π/4)-1/2tan(-13π/3)
=sin(3π+π/3)-√2cos(19π/4)+1/2tan(13π/3)
=sin(3π+π/3)-√2cos(4π+3π/4)+1/2tan(4π+π/3)
=sin(π+π/3)-√2cos(3π/4)+1/2tan(π/3)
=-sin(π/3)-√2cos(3π/4)+1/2tan(π/3)
=-√3/2-√2*(-√2/2)+1/2*√3
=1
=sin(3π+π/3)-√2cos(19π/4)+1/2tan(13π/3)
=sin(3π+π/3)-√2cos(4π+3π/4)+1/2tan(4π+π/3)
=sin(π+π/3)-√2cos(3π/4)+1/2tan(π/3)
=-sin(π/3)-√2cos(3π/4)+1/2tan(π/3)
=-√3/2-√2*(-√2/2)+1/2*√3
=1
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