How do you evaluate $-sin ((4pi)/3)$ ?

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Answer 1 · 2016-05-24T06:53:32

$"solution :"sqrt3/2$

$-sin((4pi)/3)= ?$

$((4pi)/3)=pi+pi/3$

$sin(a+b)=sin a*cos b+cos a*sin b$

$sin(pi+pi/3)=sin pi*cos pi/3+cos pi*sin pi/3$

$sin pi=0$

$cos pi=-1$

$sin( pi/3)=sqrt3/2$

$cos(pi/3)=1/2$

$-sin((4pi)/3)=0*1/2-1*sqrt3/2$

$-sin((4pi)/3)=-sqrt3/2$

$"solution :"sqrt3/2$

How do you evaluate -sin ((4pi)/3)-sin ((4pi)/3)?