Question

f(X)=|sinx|/cosx的单调性是什么

Answer 1

1.当x∈[2kπ,2kπ+π]时f(x)=tanx

2.当x∈[2kπ+π,2kπ+2π]时f(x)=-tanx

作图我们易发现函数减区间为(2kπ-π/2,2kπ],[2kπ+π,2kπ+3π/2);增区间为[2kπ,2kπ+π/2),(2kπ+π/2,2kπ+π]