=
2 |
π |
4 |
最小正周期為2π,(5分)
由x?
π |
4 |
π |
2 |
3π |
4 |
(Ⅱ)當(dāng)f(x)=0時(shí)解得tanx=
1 |
2 |
cos2x |
1+sin2x |
cos2x?sin2x |
(cosx+sinx)2 |
=
cosx?sinx |
cosx+sinx |
1?tanx |
1+tanx |
1 |
3 |
x |
2 |
x |
2 |
x |
2 |
x |
2 |
cos2x |
1+sin2x |
2 |
π |
4 |
π |
4 |
π |
2 |
3π |
4 |
1 |
2 |
cos2x |
1+sin2x |
cos2x?sin2x |
(cosx+sinx)2 |
cosx?sinx |
cosx+sinx |
1?tanx |
1+tanx |
1 |
3 |