Source of equal sign
In the mathematics books of 15 and 16 centuries, words were also used to express the equal relationship between the two quantities. For example, in some formulas at that time, the word aequ or aequaliter was often written, meaning "equal".
1557, British mathematician Colder said in his paper "The Grindstone of Wisdom": "In order to avoid boring repetition of the word isaequalleto (equal to), I have carefully compared many figures and symbols, and feel that there are no parallel equal-length line segments in the world with the same meaning."
Therefore, Colder creatively uses two parallel and equal line segments "=" to represent "equality", and "=" is called equal sign. Replacing the word equal sign with equal sign is an improvement in mathematics. Limited by the historical conditions at that time, the equal sign invented by Colder was not immediately adopted by everyone.
In history, others have used other symbols to express equality. For example, the mathematician Descartes once used ∞ to mean "equality" in his book Geometry published in 1637. Until17th century, the German mathematician Leibniz strongly advocated the use of "=" in various occasions. Because of his great reputation in mathematics, the equal sign is gradually recognized by the world.
Combine the two symbols "=" of ">" organically and get the symbol "≥". When one value is greater than another value or two numbers are equal, the greater than or equal sign "≥" is used, which is read as "greater than or equal to" and sometimes called "not less than".
For any two real numbers A and B, their corresponding points A and B can be found on the same axis. If point A is to the right of point B or A and B coincide, then A ≥ B..
Similarly, put "
Less than or equal to is a method to judge that the value on the left side of inequality is less than or equal to the value on the right side of inequality, which often appears in various mathematics or programming. In a proposition, less than or equal to is less than or equal to, as long as one condition is met.
Unequal symbol: "≦" is a symbol indicating "unequal" relationship. "≦" and "=" have opposite meanings and are often used in mathematics, such as a+ 1≠a+5.