a |
b |
π+2x |
4 |
=
1-cos2(
| ||
2 |
=2[1-cos(
π |
2 |
=2sinx(1+sinx)+1-2sin2x
=2sinx+2sin2x+1-2sin2x=2sinx+1
所以f(x)=2sinx+1.
(Ⅱ)f(ωx)=2sinωx+1
根據(jù)正弦函數(shù)的單調(diào)性:2kπ-
π |
2 |
π |
2 |
解得f(x)的單增區(qū)間為[-
π |
2ω |
π |
2ω |
又由已知f(x)的單增區(qū)間為[-
π |
2 |
2π |
3 |
所以有[-
π |
2 |
2π |
3 |
π |
2ω |
π |
2ω |
即
|
3 |
4 |
所以ω的取值范圍是(0,
3π |
4 |