I suck at math, please divulge resources

On several different occasions I've brought up the Wikipedia page on discrete cosine transforms and hoped to understand it. This selection was made because DCTs are apparently fundamental algorithms for lossy data compression like that found in JPEGs or MP3s or whatever. I want to be able to write decoders for these things -- I've poked around in mplayer's source and want to change stuff, want to create a JPEG decoder as proof-of-concept to myself, etc.

But, here's the hitch: I have no mentionable background in mathematics. I got up to geometry in high school (i.e., I know cosines in triangles but have no idea what a cosine wave is, how it works, and/or how they're related if at all). Where can I learn all of the things I need to learn for these things to make sense to me, and to become blessed with the skills and understanding necessary to create and/or decode such algorithms? I need something somewhat simple and plain, something I don't have to chain through five hundred articles to understand -- that's the problem with WP; I don't understand one thing, so middle-click it, do that about ten times per math article, including on the articles I opened to understand the first article, and there's a never-ending lot of WP articles for me to read, and that's not really tenable. I need something focused on teaching, not necessarily technical precision and exhaustiveness.

I know what a logarithm is, I looked it up. I've also tried #math on Freenode but those dudes just don't know how to talk to someone without any mathematical training. Ask for a simple explanation there, it's usually kind of funny.

Please help me. Thanks. : )

Math requires work. Euclid said, "In geometry there is no royal road."

The DCT is a complicated thing to "understand", and I'm not sure I do myself. I would guess that the people who wrote the code you're seeking to modify didn't necessarily understand it either - they may simply have coded the formulae they were given.

So don't despair. You can learn things like this, but you can't do it all at once, and you can't do it quickly. You need to start somewhere.

What do you really want to know?

Here's what I would do:

1) Look at a signals and system course online.

2) Look at the course's prerequisites.

3) Do you understand concepts in the pre-req? If not, goto 2)

4) Once you get to a course you understand reasonably, move on to the next course you don't understand. Do this (unwind the stack) until you reach the signals and systems course.

A reasonable chunk of an electrical engineer's education is required to get to the point you wish to reach, so there is a lot of effort involved.

edit: that said, this link might also be helpful: http://www.redcedar.com/learndsp.htm

Hmm... I guess these could work...

http://www.coolmath.com/algebra/index.html

http://www.purplemath.com

If you want video tutorials, this might work:

http://www.youtube.com/user/khanacademy

For a calculus resource based on analogies and stories, try this:

http://www.karlscalculus.org/

Trying to create an implementation of a lossy compression is a bit over-the-top, especially when you are trying to learn it through Wikipedia. Try a Google search and filter through those results. Maybe there will be a less technical, but still informative explanation. Also try Youtube!

http://www.youtube.com/watch?v=sckLJpjH5p8

(Haven't watched it all the way through)

Going from basic Trigonometry all the way to Discrete Fourier Transforms isn't exactly a 'overnight-hack' type of thing. Grokking everything will take a lot of time, if you do attempt it. Please don't hurt yourself.