sin2x=2sinxcosx
cos2x=2cos²x-1
所以f(x)=5/2sin2x-5√3(1+cos2x)/2+5√3/2
=(5/2)sin2x-(5√3/2)cos2x
=5(1/2sin2x-√3/2cos2x)
=5(sin2xcosπ/6-cos2xsinπ/6)
=5sin(2x-π/6)
1
sin2x=2sinxcosx
cos2x=2cos²x-1
所以f(x)=5/2sin2x-5√3(1+cos2x)/2+5√3/2
=(5/2)sin2x-(5√3/2)cos2x
=5(1/2sin2x-√3/2cos2x)
=5(sin2xcosπ/6-cos2xsinπ/6)
=5sin(2x-π/6)
1