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已知函数f(x)=cos^2(x-π\/6)-sin^2
解答:提示:本题主要考查三角函数的恒等变换及化简求值,正弦函数的定义域、值域,需要细心。【数不胜数】团队为您解答,望采纳O(∩_∩)O~
已知函数f(x)=cos^2(x-π\/6)-sin^2x
=cos²(π\/12)-sin²(π\/12) 两倍角公式 =cos[2(π\/12)]=cosπ\/6 =√3\/2 f(x)=cos^2(x-π\/6)-sin^2x =(2cos^2(x-π\/6)-1+1)\/2+(1-2sin^2x-1)\/2 =[cos(2x-π\/3)+cos2x]\/2 =(cos2xcosπ\/3+sin2xsinπ\/3+cos2x)\/2 =根号3(2分之根号3...
已知函数fx=cos^2(x-pai\/6)-sin^2
f(x) =[cos(x-π\/6)]^2 - (sinx)^2 = [(√3\/2)cosx + (1\/2)sinx]^2 - (sinx)^2 = (1\/4)( 3(cosx)^2 + 2√3sinxcosx -3(sinx)^2 )= (1\/4) ( 3cos2x + √3sin2x )= (√3\/2)((√3\/2)cos2x+ (1\/2)sin2x)= (√3\/2)sin(2x+π\/3)max f(x) ...
已知X,X+兀\/2是函数f(x)=cos^2(wx-兀\/6)-sin^2wx(w>0)
(1)解析:因为,函数f(x)=sin(2wx一兀\/6)十1\/2(w>0)的最小正周期为兀 所以,2w=2π\/π=2==>w=1 (2)解析:因为,f(x)=sin(2x-π\/6)+1\/2 单调增区间:2kπ-π\/2<=2x-π\/6<=2kπ+π\/2==>kπ-π\/6<=x<=kπ+π\/3 因为,区间[0,2兀\/3]f(0)=sin(-π\/6)+...
f(x)=cos方(x+π\/6)+1\/2cos(2x-π\/6)
=-1\/2(1\/2cos2x+√3\/2sin2x)=-1\/2sin(2x+π\/6)所以,最小正周期为:T=π;因为sin2x的对称轴为:x=π\/4+kπ\/2 所以f(x)图像对称轴的方程为:x=(π\/4-π\/6)+kπ\/2=π\/12+kπ\/2 (2) 因为 -π\/12≤x≦π\/12 所以-π\/6≤2x≤π\/6 所以0≦2x+π\/6≦π\/3 由正弦...
已知函数f(x)=cos^2x\/2-sinx\/2cosx\/2-1\/2,求f(x)的最小正周期和值域,若...
=1\/2*(cosx-sinx)=√2\/2cos(x+π\/4)所以函数的最小正周期为 T=2π 值域为[-√2\/2,√2\/2]f(a)=√2\/2cos(x+π\/4)=3√2\/10 cos(a+π\/4)=3\/5 cos2(x+π\/4)=cos(2x+π\/2)=-sin2x sin2a=-cos2(a+π\/4)=-2cos^2(a+π\/4)+1=-2*9\/25+1=7\/25 ...
已知函数f(x)=sincos(x+π\/6)-sin∧2x
答:f(x)=sinxcos(x+π\/6)-(sinx)^2 f(x)=sinx*[ cosxcos(π\/6)-sinxsin(π\/6) ]-(sinx)^2 f(x)=(√3\/2)sinxcosx-(1\/2)(sinx)^2-(sinx)^2 f(x)=(√3\/4)sin2x-(3\/2)(sinx)^2 f(x)=(√3\/4)sin2x-(3\/4)(1-cos2x)f(x)=(√3\/2)*[(1\/2)sin2x+(...
f(x)=cos平方二分之x 减去sin平方二 分之x然后*sinx
f(x)=[cos^2(x\/2)-sin^2(x\/2)]*sinx=cosxsinx=sin2x\/2;所以,函数 f(x)的值域为[-1\/2,1\/2];sinx的单调增区间为[2kπ-1\/2π,2kπ+1\/2π],所以函数 f(x)的单调增区间为:[kπ-1\/4π,kπ+1\/4π]。
已知函数f(x)= cos^2x+ sin^2x,求f(x)
∫cosx\/(sinx+cosx) dx=(1\/2)(x+ln|sinx+cosx|) + C。(C为积分常数)解答过程如下:∫cosx\/(sinx+cosx) dx = (1\/2)∫[(cosx+sinx)+(cosx-sinx)]\/(sinx+cos)] dx = (1\/2)∫ dx + (1\/2)∫(cosx-sinx)\/(sinx+cosx) dx = x\/2 + (1\/2)∫d(sinx+cosx)\/(sinx+...
已知函数f(x)=sin(2x-π\/6)-2cos^2x-1(x∈R),(1)求函数f(x)的单调递...
见图 解:(I)f(x)==sin2x+cos2x=sin(2x+).令 2kπ-≤(2x+)≤2kπ+,可得 kπ-≤x≤kπ+,k∈z.即f(x)的单调递增区间为[kπ-,kπ+],k∈z.(II)在△ABC中,由,可得sin(2A+)=,∵<2A+<2π+,∴<2A+= 或,∴A= (或A=0 舍去).∵b,a,c...