Rank of elliptic curves allied to certain cyclic extensions of degree 4 and 6. Quelques remarques à propos des invariants \(c_ 4\), \(c_ 6\) et \(\Delta\) d'une courbe elliptique. (Some remarks about the invariants \(c_ 4\), \(c_ 6\) and \(\Delta\) of an elliptic curve) 