sin(11*pi/3)=?

sin(11*pi/3)=? sin pi/12-根号3cos pi/12= tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a) cos(pi/4-a)=1/7,sin(3pi/4+b)=11/14cos(pi/4-a)=1/7sin(3pi/4+b)=11/14 pi/4 sin(pi/7)^2+sin(2pi/7)^2+sin(3pi/7)^2=怎么算 log((sin(5))^2)-3+pi=? log((sin(30))^2)-3+pi= 证明sin(pi/n)*sin(2pi/n)*sin(3pi/n)*…sin((n-1)pi/n)=n/(2^(n-1)) sin(pi/12)=? sin(PI/2+a)=-4/5 a属于(Pi,3pi/2)则cos(Pi/3-a)为 sin(pi/4+2a)sin(pi/3-2a)=1/4,a属于(pi/4,pi/2),求2sin^2a+tana-cota-1 y=sin(x+pi/3)sin(x+pi/2)的最小正周期是什么 三角函数恒等变形证明sin( pi/3 ) + sin( 2*pi/3) + ...+ sin( n * pi/3)= 2 sin (n * pi /6) * sin( (n+1) * pi /6) (n 为任意整数) f(a)=sin(pi-a)cos(2pi-a)tan(-a+3pi/2)/cos(-pi-a) 求 f(-31pi/3)的值 a,b∈（3pi/4,pi）,sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos（a+pi/4）= 已知a,b,属于（3pi/4,pi),sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos(a+pi/4)=? sin(pi/4+2a)sin(pi/4-2a)=1/4,a(pi/4,pi/3),q:2sin2 a+tana-cota-1 cosa=2/3 a是第四象限角求sin(a-2Pi)+sin(-a-3Pi)cos(a-3Pi)/cos(Pi-a)-cos(-Pi-a)cos(a-4Pi)