已知函数f(x)=cos二分之x

f(x)=cosx/2(sinx/2+√3cosx/2)-√3/2=sinx/2cosx/2+√3cos²x/2-√3/2=1/2sinx+√3/2(1+cosx)-√3/2=sinxcos

f(x)=cos^2x+sinxcosx=1/2(1+cos2x)+1/2sin2x=1/2sin2x+1/2cos2x=√2/2(√2/2sin2x+√2/2cos2x)=√2/2sin(2x+π/

f(x)=(√3/2)sinx+(1/2)cosx+1=sin(x+π/6)+1单调减区间为2kπ+π/2≤x+π/6≤2kπ+3π/2化简得：2kπ+π/3≤x≤2kπ+4π/3,即单调减区间为[2

派再问：求过程再答：再答：给好评再问：三角形3边ABC满足B^2=AC求f(B的取值范围。。)再答：先给好评，立马帮你解决再答：应该是abc吧？再问：嗯。再问：？

再问：第一问，最后你开头写的是x6吗？再答：x属于

√3sinx/2+cosx/2=y/cosx/2=1/cosx/2则√3sinx/2cosx/2+cos²x/2=1√3/2sinx+1/2(cosx+1)=1sin(x+π/6）=1/2,

（1）由f（x）=cosx+根号3cos（x+二分之兀）化简得：f(X)=-2sin(x-π/6)要f(X)有最大值,则sin(x-π/6)=-1故：X-π/6=-π/2+2Kπ,K∈Z得出X=-π/

f(x)=根号3/2sin2x-cos^2x-1/2=根号3/2sin2x-(cos2x+1)/2-1/2=sin2xcosPai/6-sinPai/6cos2x-1=sin(2x-Pai/6)-1故

解题思路：化简解析式，代性质求解.........................................解题过程：

f(x)=√3/2sin2x-3/2cos2x=√3(1/2sin2x-√3/2cos2x)=√3sin(2x-π/3)f(x)最小正周期T=2π/2=π由2kπ-π/2≤2x-π/3≤2kπ+π/2

f(x)=根号3cos^x+sinxcosx-根号3/2=根号3*(1+cos2x)/2+sin2x/2-根号3/2所以f(派/8)=根号3*(1+cos派/4)/2+sin(派/4)/2-根号3/2

f(x)=2sin(派-x)cosx=2sinxcosx=sin2x最小正周期T=2π/2=π-π/6

1．y=1/4(1+cos2x)+√3/4sin2x+1=1/2sin(2x+π/6)+5/4当2x+π/6＝2kπ+π/2,即x＝kπ＋π/6时,ymax＝7/4.自变量x的集合{x│x＝kπ＋π/

因为cos(a+b)=cosacosb-sinasinbcos(a-b)=cosacosb+sinasinb相加得cos(a+b)+cos(a-b)=2cosacosb即cosacosb=[cos(a

f(x)=cos(3x/2)cos(x/2)-sin(3x/2)sin(x/2)-2sinxcosx=cos(3x/2+x/2)-2sinxcosx=cos2x-sin2x=√2(√2/2*cos2x

√3sinx/2+cosx/2=y/cosx/2=1/cosx/2则√3sinx/2cosx/2+cosx/2=1√3/2sinx+1/2(cosx+1)=1sin(x+π/6）=1/2,cos（x+

因为f(x)=sinx*cosx+cosx平方-1/2因为sinx*cosx=1/2*sin2x；　cosx平方＝1/2(1+cos2x)所以f(x)=1/2sin2x+1/2cos2x=(√2)/2

二倍角公式

f(x)=根号3sin2x+cos2x+m+1=2sin(2x+π/6）+m+1,在该区间上,π/6

f(x)=cosx-(-sinx)=sinx+cosx=√2(√2/2*sinx+√2/2cosx)=√2(sinxcosπ/4+cosxsinπ/4)=√2sin(x+π/4)所以最大值=√2f(a