Create the Euler-Lagrange equation for the following questions (if it's necessary change the variables).
Homework Statement
$$\tag{1}\int _{y_{1}}^{y2}\dfrac {x^{'}{2}} {\sqrt {x^{'}{2}+x^{2}}}dy$$
$$\tag{2}\int _{x_{1}}^{x_{2}}y^{3/2}ds $$
$$\tag{3} \int \dfrac {y.y'} {1+yy{'}}dx...