# First order differential equation

1. Oct 19, 2011

### Xenith

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.

2. Oct 19, 2011

### Xenith

By the way, I am still studying my A levels so this isn't really advanced at all ;)

3. Oct 19, 2011

### lurflurf

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)