设函数f(X)=cos(2x+π/3)+sin方x.求函数f(x)的最大值和最小正周期设函数f(X)=cos(2x+π/3)+sin方x.设A、B、C为△ABC的三个内角,若cosB=1/3,f(C/3)=-1/4,且C为锐角,求sinA
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设函数f(X)=cos(2x+π/3)+sin方x.求函数f(x)的最大值和最小正周期设函数f(X)=cos(2x+π/3)+sin方x.设A、B、C为△ABC的三个内角,若cosB=1/3,f(C/3)=-1/4,且C为锐角,求sinA
设函数f(X)=cos(2x+π/3)+sin方x.求函数f(x)的最大值和最小正周期
设函数f(X)=cos(2x+π/3)+sin方x.设A、B、C为△ABC的三个内角,若cosB=1/3,f(C/3)=-1/4,且C为锐角,求sinA
设函数f(X)=cos(2x+π/3)+sin方x.求函数f(x)的最大值和最小正周期设函数f(X)=cos(2x+π/3)+sin方x.设A、B、C为△ABC的三个内角,若cosB=1/3,f(C/3)=-1/4,且C为锐角,求sinA
f(x)=cos(2x+π/3)+sin^2x
=cos2x/2-sin2x*√3/2+(1-cos2x)/2
=1/2-sin2x*√3/2
令f(x)=-1/4
1/2-sin2x*√3/2=-1/4
sin2x=√3/2
2x=60
x=30
也就是C/3=30
C=90
A+B=90
sinA=sin(90-B)=cosB=1/3