So here’s a new topic that I hope will be fun. Come here to complain and/or joke about information that WaniKani gives that is just plain wrong. Please avoid mentioning mnemonics that are obviously inaccurate on purpose to be silly/memorable. Anything else is fair game.
Here’s the one that prompted me to create this topic.
WaniKani (and jisho by the way) says that the kanji 凸 means “convex”. Of course, that kanji is not convex at all. By any definition of the word, that kanji is concave. Not to be confused with the kanji 凹 which is also concave and means concave on WaniKani.
Somewhat nerdy math stuff
A simple definition of a convex polygon from Wikipedia:
“Every internal angle is strictly less than 180 degrees.”
In the kanji 凸, two of the internal angles are 270 degrees.
Even nerdier math stuff
And here’s a definition of a convex set from Wikipedia:
“In convex geometry, a convex set is a subset of an affine space that is closed under convex combinations. More specifically, in a Euclidean space, a convex region is a region where, for every pair of points within the region, every point on the straight line segment that joins the pair of points is also within the region.”
Which in layman’s terms simply means that since I can draw this red line between two points in the kanji that go outside the kanji, it’s not convex.
And thus concludes my complaint about inaccurate math definitions on WaniKani.
Thank you for voicing this