函数y=2cos² sin2x的最小值

由倍角公式：cos2x=2cos²x-1,得：cos²x=(1+cos2x)/2所以,y=(√3/2)(1+cos2x)+(1/2)sin2x=(1/2)sin2x+(√3/2)c

cos(2x+(π/3))=cos(-2x-π/3)=sin(π/2+2x+π/3)=sin(2x+5π/6)=sin[2(x+5π/12)]左加右减,即由y=sin2x向左平移5π/12个单位,选A

sin2x=cos(π/2-2x)=cos(2x-π/2)=cos[2(x-π/4)];cos(2x+π/6)=cos[2(x+π/12)]所以将sin2x向左平移π/3可得到cos(2x+π/6).

可以根据：asinα+bcosα=√(a^2+b^2)*sin(α+θ),其中θ由a,b的符号和tanθ=b/a确定具体到这题,就是：y=√[(√3+2)/2]^2+(1/2)^2*sin(2x+θ)

y=2cos平方x+sin2x/1+tanx=2(sinx+cosx)cosx/[(cosx+sinx)/cosx]=2cos^2x=cos2x+10

y=sin2x-2cos²x=sin2x-cos2x-1=根号2sin（2x+π/4）-1所以最大值为（根号2-1）,最小值为（-根号2-1）

y=cos(2x+π/3)=cos(-2x-π/3)=sin[π/2-(-2x-π/3)]=sin(2x+5π/6)=sin[2(x+5π/12)]所以只要向左移5π/12个单位

解答过程见下图：

∵y＝cos(2x+π3)＝sin(2x+5π6)＝sin2(x+5π12)，只需将函数y=sin2x的图象向左平移5π12个单位得到函数y＝cos(2x+π3)的图象．故选A．

y=（1/2）sin2x+根号3cos^2x-（根号3）/2=（1/2）sin2x+根号3/2cos2x=sin2xcosπ/3+sinπ/3cos2x=sin(2x+π/3)

首先y=sin2x+2（cosx-sinx）+3,令cosx-sinx=t属于【-√2,√2】,所以y=-t^2+2t+4,由此易得其最小值为5.

y=√3cos²x+1/2sin2x=√3/2(cos2x+1)+1/2sin2x=√3/2cos2x+1/2sin2x+√3/2=sin(π/3)cos2x+cos(π/3)sin2x+√

向右移动π/8

最大值是（根号2）－1

解y=2cos^2x+sin2x-2=2cos^2x-1+sin2x-1=cos2x+sin2x-1=√2（√2/2sin2x+√2/2cos2x）-1=√2sin（2x+π/4)-1≤√2-1故y=

cos^2x=cos2x+1所以原式等于二分之根号三倍的（cos2x+1)+1/2sin2x化简得sin(2x+60)+二分之根号三最大值就是1+二分之根号三

y=2cos²x-1+1+sin2x=sin2x+cos2x+1=√2(sin2x*√2/2+cos2x*√2/2)+1=√2(sin2xcosπ/4+cos2xsinπ/4)+1=√2si

y=[sin2x+sin(2x+π/3)]/[cos2x+cos(2x+π/3)]=[sin2x+sin2xcosπ/3+cos2xsinπ/3]/[cos2x+cos2xcosπ/3-sin2xsi

1.定义域x≠kπ+π/2关于原点对称f(x)=|sin2x|-x*tanxf(-x)=|sin(-2x)|-(-x)*tan(-x)=|sin2x|-(-x*(-tanx))=|sin2x|-x*t

y'=2cos(sin2x)×[cos(sin2x)]'=2cos(sin2x)×[-sin(sin2x)]×(sin2x)'=-sin(2sin2x)×2cos2x=-2cos2xsin(2sin2