答：1）cosx-√3sinx=1(1/2)cosx-(√3/2)sinx=1/2cos(x+π/3)=1/2x+π/3=2kπ+π/3或者x+π/3=2kπ-π/3所以：x=2kπ或者x=2kπ-2π/3,k∈Z2）7cosx+3cos2x=07cosx+6(cosx)^2-3=0(2cosx+3)(3cosx-1)=0所以：2cosx+3=...