Help Differential Equations types

[BrettJimison]

Homework Statement

Good day all,

My professor gave my class a packet of about 40 differential equations.
I for the life of me cannot figure out how t solve these last 4!
I also have an exam tomorrow morning, and would like finish these last few.

I don't need them solved out, I would just like to know what kind they are a maybe a hint to get started on them!
NOTE: They WILL be one of the following types:

seperable
Bernoulli
Exact
Linear
Homogeneous

Homework Equations

1) (2x+1)dx+((x^(2)-y)/x)dy=0

2)(cos2y-sinx)dx+(-2tanxsin2y)dy=0

3)(x^(2)y+xy-y)dx+(x^(2)y-2x^(2))dy=0

4)dy/dx=(-3x^(2)y-y^(2))/(2x^(3)+3xy)[/B]

The Attempt at a Solution

I have tried all sorts of ways, some take a page plus. I can't tell of these have obvious solutions or if there is a trick. I am a little worn out after solving 35 of them.
Any help would be greatly appreciated!
Thanks!

 

[Shinaolord]

I think the 3rd one is exact, but I computed the partial derivatives in my head, so double check before you take my word on it.Actually nvm I don't think it is.