cos^4(x)-sin^4(x)等于?是cos^2(x)还是cos2x
cos^4(x)-sin^4(x)等于?是cos^2(x)还是cos2x
[sin^2(x)-cos^2(x)] 为什么等于-cos2x
f(x)=(1+cos2x)/[4sin(pai/2+x)]-asin(x/2)cos(pai-x/
已知函数f(x)=(6cos^4x+5sin^2x-4)/cos2x
求证:sin(π/4+x)/sin(π/4-x)+cos(π/4+x)/(π/4-x)=2/cos2x
求函数sin^4 x+cos^4 x-2cos2x的周期
1.y=cos^4x+sin^4x 求周期 2.y=(sin2x+sin(2x+π/3))/( cos2x+cos(2x
已知函数f(x)=(6cos^4x+5sin^2x-4)/cos2x 判断f(x)的奇偶性
y=sin^2x-3sinxcosx+4cos^2x是否等于y=sin^2x+cos^2x+3cos^2x-3/2*si
sin(sin(sin(sin(x)=cos(cos(cos(cos(x),X等于多少?
已知sin x/2 -- 2cos x/2=0.(1)求tan x的值.(2)求 cos2x/(√2cos(π/4+x)
已知4sin^2x-cos^2x+3cosx=0求(cos2x-cos^2x)/(1-cot^2x)