2sin(x+π/4)sin(x-π/4)=?

已知函数fx=（1+1/tanx）sin^x-2sin（x+π/4)sin（x-π/4） y=sin(π/4+x/2)sin(π/4-x/2) =sin(π/4+x/2)sin[π/2-(π/4+x/2)] 已知函数f(x)=sin^2 x+2根号3sinxcosx+sin(x+π/4)sin(x-π/4),x属于R,求f(x 已知f(x)=cos^2x+sinxcosx g(x)=2sin(x+π/4)sin(x-π/4) 1.已知sin(π/6-x)=1/4,sin(π/6+2x)=? 已知函数y=2sin(2x-π/4)-2根号2sin^2x 已知函数f(x)=cos(2x-π/3）+2sin(x-π/4）sin(x+π/4)=sin(2x-π/6) , 已知sin(π/2-x)+sin(π-x)/cos(-x)+sin(2π-x)=2009,则tan(x+5π/4)等于? 证明sinx+siny+sinz-sin(x+y+z)=4sin((x+y)/2)sin((x+y)/2)sin((x+ 求证:sin(π/4+x)/sin(π/4-x)+cos(π/4+x)/(π/4-x)=2/cos2x 已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4) f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+/4π) 三角函数