函数fx=cos^2x-1 2的最小正周期

fx=-√3cos2x-sin2x=-2sin(2x+π/3)所以最小正周期为πf'x=-4cos(2x+π/3),f'x>0时递增x在（π/12,π/3)上递增f'x=0,x=π/12.极小值f(π

f(x)=2cos²x+2√3sinxcosx=1+cos(2x)+√3sin(2x)=2[(√3/2)sin(2x)+(1/2)cos(2x)]+1=2sin(2x+π/6)+1当sin(

f(x)=cos2x+根号3sin2x=2sin(2x+π/2）所以周期为π对称轴2x+π/2=π/2+kπ（k是整数）即x=kπ/2k是整数单调区间-π/2+2kπ

f(x)=cosx-cos(x+π/2)=cosx+sinx=3/4sin^2x+cos^2x+2sinxcosx=9/162sinxcosx=sin2x=9/16-1=-7/16

(1)f（x）=sin（2x+π/6）-cos（2x+π/3）+2cos²x=sin2xcosπ/6+cos2xsinπ/6-[cos2xcosπ/3-sin2xsinπ/3]+2cos&#

若cosα=3/5.α属于(3π/2,2π),sinα=-4/5把f(2α+π/3)代入fx=√2cos(x-π/12),化简原式=cos2α-sin2αcos2α-sin2α怎么化简的就不用我说了吧

f(x)=cos²x-2cos²x/2=cos²x-2*1/2*(cosx+1)=cos²x-cosx-1=(cosx-1/2)²-5/4这是复合函数

f(x)=sin²x+√3sinxcosx+2cos²x,=√3sinxcosx+cos²x+1=√3/2sin2x+1/2(1+cos2x)+1=√3/2sin2x+1

令t=sinx则f=(1-t^2)+2t=-t^2+2t+1=-(t-1)^2+2因为|t|

你确定是5sinx-cosx不是5sinxcosx?如果是5sinxcosx,那么f(x)=5sinxcosx-5√3cos^2x=5sin2x/2-5√3[(1+cos2x)/2]=5sin2x/2

fx=2cos^2x+2根号3sinxcosx-1=2cos^2x-1+2根号3sinxcosx根据倍角公式,sin2α=2sinαcosαcos2α=2cos^2（α）-1fx=cos2x+根号3s

f(x)=cos(2x-4π/3)+2cos^2x=cos(2x-4π/3)+cos2x+1=2cos(2x-2π/3)cos2π/3+1=1-√3cos(2x-2π/3)1.当cos(2x-2π/3

f(x)=[2cos^2(x/2)-1]+sinx=cosx+sinx=√2sin(x+π/4)∵x∈R∴x+π/4∈R∵f(x)=sinx∈(-1,1)∴f(x)=√2sin(x+π/4)∈(-√2

f(x)=cos(2x-π/3)-cos2x=1/2cos2x+√3/2sin2x-cos2x=√3/2sin2x-1/2cos2x=sin(2x-π/6)最小正周期T=2π/2=π(2)0

f(x)=2sinxcosx-(2cos²x-1)=sin2x-cos2x=√2sin(2x-π/4)所以值域是[-√2,√2]

f(x)=2cos²(x/2)-√3sinxf(x)=2cos²(x/2)-2√3sin(x/2)cos(x/2)f(x)=2cos(x/2)[cos(x/2)-√3sin(x/2

设函数fx=2cos^2(π/4-x)+sin(2x+π/3)-1=cos(PI/2-2x)+sin(2x+PI/3)=sin(2x)+sin(2x)/2+cos(2x)*sqrt(3)/2=sqrt

(1)∵cos2x=2cos^2x-1∴f(x)=1/2+cos(2x+π/6)/2对称轴2x0+π/6=π+2kπx0=5π/12+kπg(x0)=1+1/2sin(5π/6+2kπ)=5/4（2）

解f(x)=2cos^2x+2√3sinxcosx-1=√3sin2x+cos2x=2sin(2x+π/6)∴最小正周期为：2π/2=π再答：不懂追问再问：在三角形ABC中，角ABC所对的边分别是ab