Question
Solve:
tan y dx + sec2 y tan x dy = 0.
Solution
The given differential equation is
tan y dx + sec2 y tan x dy = 0 or sec2 y tan x dy = - tan y dx
Separating the variables, we get,

Integrating,

tan y dx + sec2 y tan x dy = 0 or sec2 y tan x dy = - tan y dx
Separating the variables, we get,

Integrating,

