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8.5 #20

So I finally solved this one after a bit of brain failure. In case anyone else gets the same point as me and is wondering how in the world to integrate

$ \int\frac{d\theta}{1+\cos\theta} $

Stop, you've went too far. Go back a few steps until you have something like:

$ \int\frac{d\theta}{\cos^2\theta} $

And integrate from there. If you don't know how, remember your very basic trig identities. Like that 1/cos(x) = sec(x). Yeah, that should help.

Boy did I feel stupid when I finally figured it out, like ten minutes after seeing if I had to integrate by parts and then asking another math nerd on my floor to help (disclaimer: he didn't see it at first either. It wasn't until we sat down and were really gonna start working on it that I was like, "Hey, wait, what is one over cosine squared? Isn't that secant squared?"). So yeah, stupid moment. Hope no one else gets as stuck as I did. But hey, that's what this is for, right?

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Abstract algebra continues the conceptual developments of linear algebra, on an even grander scale.

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