亲
,请看如下解答
(1)
(3√15sinx)(3√5)cosx
=15√3sinxcosx
=(15√3/2) sin2x
周期T=2π/2=π
单调增区间:[-π/4+kπ/2,π/4+kπ/2]
单调减区间:[π/4+kπ/2,3π/4+kπ/2] k∈Z
最大值15√3/2
最小值-15√3/2
(2)
3/2 cosx-√3/2 sinx
=√3 (√3/2 cosx- 1/2 sinx)
=√3(sinπ/3cosx-cosπ/3sinx)
=√3sin(π/3-x)
=-√3sin(x-π/3)
周期T=2π
由π/2+2kπ≤x-π/3≤3π/2+2kπ
得5π/6+2kπ≤x≤11π/6+2kπ
递增区间:[5π/6+2kπ,11π/6+2kπ] k∈Z
最大值√3
最小值-√3