The best way to learn it is by using it. Matlab is based on linear algebra package geared for control engineers. The spin-off called Simulink proves the statement; Simulink is a grafic editor that looks like an analog computer (i.e. electrical ordinary differential equation solvers).
Nowadays, Matlab branched tremendously, from ODE's to financial application, image processing and wht not. However, Matalb remains a dynamic systems modelling / analysis tool (i.e. anything around us).
In order to avoid frustrations, borrow a basic control system design book so you can understand the "flavor" of Matlab / Simulink. Next, define well what you want to do and stick with it, else you'll get lost.
I have seen many enthusiasts loosing interest out of frustration, as well as many projects falling flat, one of the resons being in all cases the neglect of the Matlab "flavor".
There is a lot of good information in the help and demo menus in Matlab itself. Anyone with a bit of patience can learn a considerable amount by perusing these files that are included with the program!
Good luck,
fm!
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"Your theory is crazy, but it's not crazy enough to be true." - Niels Bohr
Matlab is too huge for anybody I know on earth to learn it from top to botton.
I suggest you to start learning the matlab basics by following the help tutorials at "mathworks" and then learn each toolbox you need one at a time.
Another try would be to google "matlab for beginners" and you will get a lot of tutorials from different universities.
Some of the toolboxes are very easy to use once you get the general Matlab feeling. But it gets more and more complicated once you want a deeper insigth.
So my advice is:
Stand on good ground, and spend all the time you need to learn the basics. Then everything will be faster.
Good luck!
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If you only have a hammer, you tend to see every problem as a nail. Abraham Maslow