2sin(x-π/4)×sin(x+π/4)怎么化简成（sinx-cosx)(sinx+cosx),详细过程,谢谢了!

2sin(x+π/4)sin(x-π/4)=? sin^2(π/4 +x) sin(x+π/4) 求证:(sin 2x /(1-cos 2x) )·(sin x /(1+sin x))=tan (π/4-x/2). f(x)=（1+cotx)sin^2x-2sin(x+π/4)sin(x-π/4)还有一题, 已知函数f(x)=(1+1 anx)sin^2x+m sin(x+π/4)sin(x-π/4) sin(x+π/4)sin(x-π/4)等于什么? sin^2(π/3-x)+sin^2(π/6+x) sin(πx/2)求导 已知sin(x+π/6)=1/4,求sin(5π/6-x)+sin^2(π/3-x) 化简 sin²x+sin²(x+2π/3)+sin²(x-2π/3) 根号2sin(x+π/4)化简 sin（x+π）的奇偶性sin(x+π)的奇偶性sin(x+π/2)的奇偶性sin(x+π/4)的奇偶性 函数f(x)=2sin(x+π/4)sin(x-π/4)+sin2x的值域 求f【x】=2sin[x+π/4]sin[x-π/4]+sin2x的最大值 化简2sin^2[(π/4)+x]+根号3（sin^x-cos^x）-1 定积分0到π x*((sin(x))^2-(sin(x))^4)^(1/2) 求sin^2(2x+π/3)的导数这样写为什么不对：[sin^2(2x+π/3)]'=[sin(2x+π/3)·sin(2x+π/3)]'=2[sin(2x+π/3)]'·sin(2x+π/3)=2cos(2x+π/3)·sin(2x+π/3)=sin(4x+2π/3)