I've been having problems with this question:
(dy/dx)sinx + y*secx = (cosx)^2
Any help please?
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I've been having problems with this question:
(dy/dx)sinx + y*secx = (cosx)^2
Any help please?
(dy/dx) + y*sec x*cosec x = cosec x (cos x)^2
sec x * cosec x = 1/[sin x * cos x] = 1/[(1/2) sin 2x] = 2 cosec 2x
Integral of 2 cosec 2x = ln |tan x|
So integrating factor = tan x
tan x (dy/dx) + y*sec2 x = cos x
Integrating
y tan x = sin x + c
It all make sense now! I thought the integral of 2 cosec 2x was 2ln |tan x|, which gave me a tan sqaured. oops. Cheers. :)
I had to think about that one too but I differentiated ln |tan x| to check