cos(x-π/2)=3/5.则cos2x=
cos(x-π/2)=3/5.则cos2x=
cos[2(π-x)]=-cos2x对不对?
cos^2 x=(cos2x-1)/2
设函数f(x)=cos(2x+π/3)+1/2-1/2cos2x
已知函数f(x)=3sinxcosx-cos(2x+π3)-cos2x
已知函数f(x)=2cos2x+cos(2x+π/3)-1
已知函数f(x)=cos(2x-π3)+sin2x-cos2x.
设函数f(x)=cos(2x-π/3)-cos2x-1
已知函数f(x)=cos(2x+π/3)+sin2x-cos2x
若cos(π/2+x)=4/5,则cos2x=
已知tanx=-4/3,试化简(2+cos2x)/[(根号2)·cos(x-π/4)-sin2x]
函数f(x)=cos2x+cos(x+π/3)+sin(x+π/6)+3sin^2x的最小值