igloo myrtilles fourmis
Now that is an enigma of a site. Lots of material, but most of it is in the form of definitions. What looks like topics at the top are ads. The Author is "David Andrew Smith" but no way to contact him (except to sign up for a newsletter).
In contrast, mathworld has Eric Weisstein, Wikipedia has everybody, Cut the Knot has Alexander Bogolmony, and so on.
And what is a "Amplitudenbspnbspof"?: http://libraryofmath.com/Trigonometry_Example_Amplitudenbspnbspof_Sine_and_Cosine.html
It looks like "Amplitude of", with two non-breaking spaces? I don't know, I'm just throwing things out there.
That will be it!
Strange that it would get published like that. It makes me guess that the site is created "automatically". So the source data is probably in a database, and it gets created automatically and the results are not checked.