求证(cos^2x-sin^2x)(cos^4x+sin^4x)+1/4sin2xsin4x=cos2x
求证:sin(π/4+x)/sin(π/4-x)+cos(π/4+x)/(π/4-x)=2/cos2x
求证(cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2
求证 cos^8(x)-sin^8(x)=cos2x【1-1/2sin^2(2x)】
f(x)=(1+cos2x)/[4sin(pai/2+x)]-asin(x/2)cos(pai-x/
三角等式求证:cos^6x+sin^6x=1-3sin^2x+3sin^4x
cos^4(x)-sin^4(x)等于?是cos^2(x)还是cos2x
已知函数f(x)=(6cos^4x+5sin^2x-4)/cos2x
1.y=cos^4x+sin^4x 求周期 2.y=(sin2x+sin(2x+π/3))/( cos2x+cos(2x
求证:cosx+cos2x+...+cosnx={[cos(n+1)x/2]*[sin(n/2)x]}/[sin(x/2
已知sin x/2 -- 2cos x/2=0.(1)求tan x的值.(2)求 cos2x/(√2cos(π/4+x)
已知函数f(x)=(4cos^4x-2cos2x-1)/[sin(π/4+x)·sin^2(π/4-x)]化简
已知函数f(x)=(4cos^4x-2cos2x-1)/[sin(π/4+x)·sin(π/4-x)]化简