y=根号下cosx的定义域是?

Question

y=根号下cos x的定义域是?

Answer 1

y=根号下cos x
则 必须满足cosx>=0
所以2kπ-π/2<=x<=2kπ+π/2,k∈Z
即定义域为{2kπ-π/2,2kπ+π/2,k∈Z}