# Particular integral problem

#### Zell2

1. Homework Statement
I'm trying to find a particular integral to the differential equation on the attatched image, but I come up with two slightly different answers depending on the method I use. I suspect the problem (if it's not just me being very thick and making a silly algebra error) is the way arctan is defined but I can't see what I should do differently in either solution.

3. The Attempt at a Solution
Attatched.

Thanks

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#### HallsofIvy

Homework Helper
?? You give just the answers and they look identical to me!

#### Zell2

One has a plus thi one has a minus thi for some reason.

#### Gib Z

Homework Helper
I think you mean phi, $$\phi$$
I havent read the question, I probably wouldn't understand it, but perhaps Halls was giving a hint that its equal to zero?

#### Zell2

My mistake sorry, meant phi. I think phi's only going to be zero in a special case, for most values of a,b,c,w it's going to be non-zero.

Does anyone have any other suggestions? The second version is the one that works in the differential equation but I still can't see why the first one doesn't.
Thanks

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