首先,考虑定义域为cosx>0,解得x∈(2kπ-π/2,2kπ+π/2),k∈Z.f(x)=√[(1-cos2x)/cosx]=√[2(sinx)^2/cosx]=√{[2-2(cosx)^2]/cosx}=√[2(1/cosx-cosx)]由于cosx>0,显然,随着cosx的增大,f(x)单调减小.于是,f(x)的单...