y=ln|tanx secx|求导?

2025-06-22 16:52:54
推荐回答(2个)
回答1:

y=ln|tanx+secx|
= ln|sinx/cosx+1/cosx|
= ln|(sinx+1)/cosx|
sinx≠-1,cosx≠0
x≠2kπ-π/2且x≠kπ+π/2
∴定义域x≠kπ+π/2

当 x∈(2kπ-π/2,2kπ+π/2)时:
y= ln(tanx+secx)
y ′ = 1/(tanx+secx)* (tanx+secx)′
= * 1/(tanx+secx) * (sec²x+tanxsecx)
= secx

当 x∈(2kπ+π/2,2kπ+3π/2)时:
y= ln(-tanx-secx)
y ′ = - 1/(tanx+secx)* (-tanx-secx)′
= -1/(tanx+secx) * (-sec²x-tanxsecx)
= secx

综上,y ′ = secx

回答2:

y'=1/(tanx+secx)*(tanx+secx)'
=1/(tanx+secx)*(sec²x+tamxsecx)
=1/(tanx+secx)*secx(tanx+secx)
=secx