问题
解答题
已知函数f(x)=sin2x+2
(1)求f(x)的最小正周期和值域; (2)若x=x0(0≤x0≤
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答案
(1)易得f(x)=sin2x+
3 |
1 |
2 |
1-cos2x |
2 |
3 |
1 |
2 |
3 |
1 |
2 |
π |
6 |
1 |
2 |
所以f(x)周期π,值域为[-
3 |
2 |
5 |
2 |
(2)由f(x0)=2sin(2x0-
π |
6 |
1 |
2 |
π |
6 |
1 |
4 |
又由0≤x0≤
π |
2 |
π |
6 |
π |
6 |
5π |
6 |
所以-
π |
6 |
π |
6 |
π |
6 |
| ||
4 |
此时,sin2x0=sin[(2x0-
π |
6 |
π |
6 |
π |
6 |
π |
6 |
π |
6 |
π |
6 |
1 |
4 |
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2 |
| ||
4 |
1 |
2 |
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8 |