cos2x/(sinx-cosx)的定义域和值域

问题描述:

cos2x/(sinx-cosx)的定义域和值域

定义域:sinx-cosx≠0,x ≠ kπ+π/4
值域:[-√2,√2],因为:
cos2x/(sinx-cosx)
=(cos²x-sin²x) /(sinx-cosx)
=-(sinx+cosx)
=-√2sin(x+π/4)