已知函数f(x)=cosx?sin(x+π3)-3cos2x+34,x∈R.(1)求f(x)的最小正周期;(2)求f(x)在[-π4
已知函数f(x)=cosx?sin(x+π3)-3cos2x+34,x∈R.(1)求f(x)的最小正周期;(2)求f(x)在[-π4,π4]上的最小值和最大值....
已知函数f(x)=cosx?sin(x+π3)-3cos2x+34,x∈R.(1)求f(x)的最小正周期;(2)求f(x)在[-π4,π4]上的最小值和最大值.
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(1)∵f(x)=cosx?sin(x+
)?
cos2x+
=cosx(
sinx+
cosx)?
cos2x+
=
sinxcosx?
cos2x+
=
sinxcosx?
π |
3 |
3 |
| ||
4 |
=cosx(
1 |
2 |
| ||
2 |
3 |
| ||
4 |
=
1 |
2 |
| ||
2 |
| ||
4 |
=
1 |
2 |