log((sin(30))^2)-3+pi=

log((sin(30))^2)-3+pi= log((sin(5))^2)-3+pi=? 求 log((sin(5))^2)-3+pi log((sin(5))^2)-3+pi等于多少? 三角函数恒等变形证明sin( pi/3 ) + sin( 2*pi/3) + ...+ sin( n * pi/3)= tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a) 证明sin(pi/n)*sin(2pi/n)*sin(3pi/n)*…sin((n-1)pi/n)=n/(2^(n-1) 化简：sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a) 已知函数f（x）=cos（2x-pi/3）+2sin（x-pi)*sin(x+pi/4) 已知Sin(2x+pi/3)=1/3,求Sin(5Pi/6-4x), y=sin(x+pi/3)sin(x+pi/2)的最小正周期是什么 sin(11*pi/3)=?