1 |
2 |
| ||
2 |
3 |
=2sinxcosx+
3 |
=sin2x+
3 |
=2sin(2x+
π |
3 |
∴T=π
(Ⅱ)f(x)的减区间为2kπ+
π |
2 |
π |
3 |
3π |
2 |
π |
12 |
7π |
12 |
又∵x∈[−
π |
2 |
π |
12 |
π |
2 |
5π |
12 |
π |
12 |
π |
2 |
即f(x)在[−
π |
2 |
5π |
12 |
π |
12 |
π |
2 |
π |
3 |
3 |
π |
2 |
π |
2 |
1 |
2 |
| ||
2 |
3 |
3 |
3 |
π |
3 |
π |
2 |
π |
3 |
3π |
2 |
π |
12 |
7π |
12 |
π |
2 |
π |
12 |
π |
2 |
5π |
12 |
π |
12 |
π |
2 |
π |
2 |
5π |
12 |
π |
12 |
π |
2 |