Translation:The opposite orientation
You added an extra word ...is.
This is a trap students fall into. You wanted to make the phrase have more sense to it so you added an extra word. The computer doesn't see any difference between adding an extra word so it makes more sense or the alternative removal of a word so it makes less sense.
In French, "inverse" does not have a separate masculine and feminine form, just "inverse". http://www.larousse.fr/dictionnaires/francais-anglais/inverse/44019
Thanks for you reply! But http://en.wikipedia.org/wiki/La_Pyramide_Invers%C3%A9e
Is this some sort of an exception, or?
No, it is a different word in French. "Inverse" = "opposite" http://www.larousse.fr/dictionnaires/francais-anglais/inverse/44019 and "inversé" (f, inversée) = "inverted". http://www.larousse.fr/dictionnaires/francais-anglais/invers%C3%A9/657176