The butterfly theorem is introduced as follows:
Butterfly theorem is one of the most wonderful results in ancient Euclidean plane geometry. This proposition first appeared in 18 15 and was proved by W.G. Horner.
The name "Butterfly Theorem" first appeared in the February issue of American Mathematical Monthly (1944), with the title like a butterfly. There are countless proofs of this theorem, math lovers are still studying it, and there are various deformations in the exam. The butterfly theorem sets m as the midpoint of the inner chord PQ of a circle, and crosses m as the chords AB and CD. Let PQ where AD and BC intersect at points X and Y, then M is the midpoint of XY.
Butterflies are introduced as follows:
Butterfly is the general name of Insecta, Diptera, Lepidoptera and Papilionidae. Nearly 20,000 species have been recorded in the world, and China is rich in butterfly resources, with more than 2,000 species recorded. The tentacles of most butterflies are rod-shaped or hammer-shaped, slender and slightly thick at the bottom.
During the day, the wing interlocking device is a wing hug, and the body is slender. Butterflies are called "flying flowers" and are very beautiful insects. Most butterflies are medium and large, with wings spread between 15~260 mm and two pairs of membranous wings. The body is long and cylindrical, and it is divided into three parts: head, chest and abdomen.
The history of butterfly science is introduced as follows:
1758, Linnaeus established the binomial method of biological names, that is, the scientific name of a species consists of two parts, the former word is the noun form of the genus name of the creature, and the latter word is the species name (adjective form) of the creature, forming the scientific name. The scientific name is followed by the surname and year number of the celebrity, that is, the person who originally named the species and the time when it was named.