lagranià magnétic eléctric

d_{tt}[r] =  ( d_{t}[r]^{n}/r^{n} )


r(t) = t^{(2+(-n))}


d_{tt}[r] = t^{(-n)}


d_{t}[r(t)]^{n} = t^{n(1+(-n))}


( r(t) )^{(-n)}= t^{(2(-n)+n^{2})}