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Xenith
Oct19-11, 03:51 PM
I am asked to find the general solution to:

\dfrac{dy}{dx}\sin x + y \sec x = \cos^2 x

I don't quite know where I am going with this one; by simply looking at it, I can't seem to see what I would differentiate in order to get the left side and equally, I don't know if dividing through by and finding the integrating factor is a good idea either.

I need a nudge in the correct direction really! Sorry if I am not spotting anything glaringly obvious. I have just started looking at this topic a few hours ago.

Thanks very much in advance

Xenith
Oct19-11, 03:54 PM
By the way, I am still studying my A levels so this isn't really advanced at all ;)

lurflurf
Oct19-11, 10:36 PM
You should think of this as being
(u y)'=u' y+u y'=v'
easily solved as
y=v/u
choosing u and v are what matter.

hint: What is
tan'(x)