First, I apologize if the question doesn't fit this forum.
In a thread about Galois theory on a French math forum, I read "le sextique résolvent" and the spelling looks odd to me. I would have expected an ending in "ant" for this notion, as the derivate of a present participle.


I am therefore looking for references in French freely available online where this notion and its use are introduced and hopefully motivated. I would also like to know if this notion dates back to Galois himself or was introduced later and when.


Thanks in advance.



Resolvent in French
This should read "la résolvante sextique".


Resolvents were used before Galois - and are still used after him. For example the cubic resolvent that appears in the solution of the fourth degree equation is sometimes attributed to Lagrange. In fact Lagrange had already studied the permutations of roots of a polynomial equation and how some of them fix a given form.


