I would highly recommend shaum's outlines on calculus and differential equations, it's very begginer friendly, lots and lots of examples and exercises to test your understanding, accompanied with their solutions.
Alright so I was just messing around with Lagrangian equation, I just learned about it, and I had gotten to this equation of motion:
Mg*sin{α} - 1.5m*x(double dot)=0
I am trying to get velocity, and my first thought was to integrate with dt, but I didn't know how to. And I'm not even sure it's...