1.△ is a Greek letter, which is a common symbol in mathematics, physics, astronomy, chemistry and other disciplines. Delta (Greek letter) Delta is the pronunciation of the fourth Greek letter, capitalized δ and lowercase δ. In mathematics or physics, uppercase δ is used to represent incremental symbols, and lowercase δ is usually used to represent variables or symbols in higher mathematics. Delta is the capital letter of the Greek alphabet, and its lowercase form is delta.

2. The mathematical symbol δ, whose Chinese name is Delta symbol and English name is Delta, is used to represent incremental symbols in mathematics or physics, among which it appears in the formula for finding the root of a quadratic equation with one variable.

3.△(△) refers to the change of speed over a period of time, and △v=△x/△t is wrong. The correct value is v=△x/△t △v is generally used to calculate the acceleration a=△v/△t and △v is a vector (including magnitude and direction).

4. Enter "△" as the shortcut key. After finding the menu of the operation bar at the top of the Excel operation interface, use the shortcut key "alt+4 1463" to enter Click Insert, and enter the "△" symbol to finish.