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任意角三角函数的概念

> 对于函数 f(x)= sinx当sinx≥cosx时 cosx当sinx＜cosx时，下列结论正确的是（　　） A．函数f（x）的值域是[-1，1] B．当且仅当x=2kπ+ π 2 时，f（x）取最大值1 C．函数f（x）是以2π为最小正周期的周期函数 D．当且仅当2kπ+π＜x＜2kπ+ 5 4 π（k∈Z）时，f（x）＜0

问题：

发布时间：2024-09-13

对于函数 f(x)=

sinx当sinx≥cosx时

cosx当sinx＜cosx时

，下列结论正确的是（　　）

A．函数f（x）的值域是[-1，1]

B．当且仅当x=2kπ+

π

2

时，f（x）取最大值1

C．函数f（x）是以2π为最小正周期的周期函数

D．当且仅当2kπ+π＜x＜2kπ+

5

4

π（k∈Z）时，f（x）＜0

参考答案：

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