设f(x)=cos2x-2a(1+cosx)的最小值为-1/2,求a值

设f(sinx)=cos2x+1求f(cos*x) 设函数f(x)=cos(2x-π/3）-cos2x-1怎么化简? 设f(sin x)=cos2x+1,求f(cos x). 设f(x)=(sin^4 x-cos^4 x-5)/(cos2x+2). (a)证明f(x)= 3/(2 sin^2 x-3) -1 (b)求f(x)的范围 2.设f(x)=(sin^4 x-cos^4 x-5)/(cos2x+2).(a)证明f(x)= 3/(2 sin^2 x-3) -1 (b)求f(x)的范围 求函数f(x)=cos平方x+cos2x的最大值?(1+cos2x)/2+cos2x 然后怎么计算? 设函数f(x)=cos(2x-π/3)+cos2x-1,若x€[0,π/2],求f(x)的最大值及相应的x值 化简f(x)=cos(2x-π/3)-cos2x cos^2 x=(cos2x-1)/2 已知f(x)=2sinxcosx+cos2x,设f(a/2)=1/5,求sina的值 f(sinx)=3-cos 2x,则f(cos x)=?A.3-cos 2x B.3-sin2x C.3+cos2x D.3+sin2x 函数f(x)=（1＋cos²2x）/(1-cos2x)的值域为 f(x)=(1-cos2x)cos^2x化简等于? f(x)=cos(2x-π/3)-cos2x-1化简 设f(x)=cos2x-2a(1+cosx)的最小值为-2/1,则a= 设f(x)=cos2x-2a(1+cosx)的最小值为-1/2,求a值 【急】cos2x+sin(π/2-x)既有最大、最小值,又是偶函数f(x)=cos2x+sin(π/2+x)=cos2x+cosx f(-x)=cos(-2x)+cos(-x)=cos(2x)+cos(x)=f(x) ∴f(x)=cos2x+sin(π/2+x)是偶函数 f(x)=cos2x+cosx=(cosx)^2+cosx-1=2(cosx+1/4)^2-9/4 当cosx=-1/4,f（x 设函数f(x)=sin2x+cos2x+1求化简