问题
填空题
函数y=sin(-2x+
|
答案
原式=-(sin2xcos
-cos2xsinπ 6
)+π 6
sin2x3
=-
sin2x+3 2
cos2x+1 2
sin2x3
=
sin2x+3 2
cos2x1 2
=cos
cos2x+sinπ 3
sin2xπ 3
=cos(2x-
)π 3
∵y=cos(2x-
)的递增区间为2kπ-π≤2x-π 3
≤2kππ 3
即kπ-
≤x≤kπ+π 3 π 6
∴y=sin(-2x+
)+π 6
cos(2x-3
)的递增区间为[kπ-π 2
,kπ+π 3
](k∈Z)π 6
故答案为[kπ-
,kπ+π 3
](k∈Z)π 6