Equations of Motion Using Lagrange?

[PaulaFrafa]

Hi, my professor asked me to proove the equations of motion of a problem. The equations that I need to find are in page 2 of the file https://docs.google.com/file/d/0BxOdCfkh6FqpUlY5TktpbDZTc2M/edit , equations 7 and 8. But, I'm having trouble with the exercise.

I uploaded my attemps. Problably I'm wrinting a wrong Lagrangian.. Does anyone have a clue about the right way? Sorry for my english, I'm not a native speaker. Thanks

 

[Shinaolord]

Can you please write your equations in latex as per forum rules?
Than perhaps I will understand what you are asking, as the link provided leads me to a page that has no equations. (I couldn't turn the page.)

For example, we can write the lagrangian of a system,$$\mathcal{L}(q, q', p, p')$$ by writing the following
\mathcal{L}(q, q', p, p')
If you prefer dot notation,
$$\mathcal{L}(q,\dot{q},p,\dot{p})$$
Where the dots are made by \dot{variable}
Ie,
$$\dot{a}$$
Double dot can be done as well,
$$\ddot{a}$$
For more specific see the FAQ.
Note: you must put "$$" at the beginning and end of the statement as it makes the forum recognize it as latex.
Cheers,