已知向量m=(cos2x,a),n=(a,2 根号3sin2x)
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f(x)=mn=√3A/2sin2x+A/2cos2x=Asin(2x+π/6)f(x)最大值是6故A=6(2)函数y=f(x)的图像向左平移π/12个单位,得到6sin(2x+π/3)再将所得图像上
m=(cosA,sinA),向量n=(2,-1),且向量m×向量n=0∴2cosA-sinA=0∴tanA=sinA/cosA=2∴f(x)=cos2x+tanAsinx=cos2x+2sinx=1-
f(x)=2sinxcosx+cos2x=sin2x+cos2x=√2sin(2x+π/4)⑴f(π/4)=1⑵2x+π/4∈〔-3π/4,5π/4〕且2x+π/4∈〔-π/2+2kπ,π/2+2kπ
FX=X1X2+Y1Y2=SIN2X-根号3COS2X=2SIN(2X-π/3)T=2π/2=πMAX=2,MIN=-2
f(x)=m.n+2=(sinx,A/2*cos2x)(√3Acosx,1)+2=√3Asinxcosx+A/2*cos2x+2=√3/2Asin2x+A/2*cos2x+2=Asin(2x+π/6)
f(x)=向量m*向量n=A[((根号3)/2)sin2x+(1/2)cos2x]=Asin(2x+pi/6)最大值为A所以:A=6
(1)a.b=cosx(cos2x-1)+sinxsin2x=cosx(1-2sin²x-1)+2sinxcosxsinx=-2cosxsin²x+2cosxsin²x=
f(x)=向量a·向量b=(1+cos2x,1)*(1,m+根号3sin2x)=1+cos2x+m+根号3sin2x=1+m+2sin(2x+π/6)===>f(x)的最小正周期是:T=2π/2=π最
f(x)=sinx*根号3Acosx+A/3cos2x=根号3A/2sin2x+A/3cos2x最大值=根号[(根号3A/2)^2+(A/3)^2]=63A^2/4+A^2/9=36A^2=36^2/
sin2x=2sinxcosxsin30°=二分之一,cos30°=二分之根号三f(x)=Asin(2x+30°)书山有路小心为上
(1)f(x)=a*b=(√3sin2x,cos2x)(cos2x,-cos2x)=√3sin2x*cos2x-cos2x*cos2x=(√3/2)sin4x-(cos4x+1)/2=(√3/2)si
f(x)=ab+m向量的积为对应坐标积的和所以f(x)=(cos2x,sin2x)*(根号3,1)+mf(x)=根号3cos2x+sin2x+mf(x)=2(根号3cos2x/2+sin2x/2)+m
f(x)=√3Asinxcosx+(A/2)cos2x=(√3/2)Asin2x+(1/2)Acos2x=Asin(2x+π/6)若f(x)的最大值为6,则A=-6或A=6.再问:A/3cos2x我想
a向量*b向量=cos2xcosx+sin2xsinx=cos(2x-x)=cosx|a向量+b向量|=根号下(cos2x+cosx)^2+(sin2x+sinx)^2=根号下2+2cosx=根号下2
∵向量a=(cos2x,sin2x)、向量b=(cosx,sinx),∴向量a+向量b=(cos2x+cosx,sin2x+sinx),向量a-向量b=(cos2x-cosx,sin2x-sinx).
y=(1+cos2x,1)*(1,√3sin2x+a)=cos2x+√3sin2x+a+1=2(1/2cos2x+√3/2sin2x)+a+1=2(sinπ/6cos2x+consπ/3sin2x)+
(1)a×b=√3sin2xcos2x-(cos2x)^2=√3/2sin4x-1/2cos4x-1/2=-cos(4x+60°)-1/2,所以cos(4x+60°)=3/5,因为52.5°
f(x)=m*n=根号3sinxcosx-1/2cos2x=根号3/2sin2x-1/2cos2x=sin(2x-Pai/6)f(A)=sin(2A-Pai/6)=12A-Pai/6=Pai/2A=P