Capital δ

Used for:

In mathematics and science, indicating the change of variables.

In mathematics, in regression analysis, the difference between the measured value (true value or accurate value) and the predicted value of regression equation.

Delta represents b2-4ac in unary quadratic equation ax2+bx+c=0(a≠0) or quadratic function y=ax2+bx+c(a≠0). In the equation, if δ ≥ 0, the equation has a real number solution (if δ >; 0, the equation has two unequal real number solutions; If δ = 0, the equation has two equal real number solutions), if δ >; 0, the image has two intersections with the x axis; If δ = 0, the image has only one intersection with the X axis; If δ

In physics, it means the change of physical quantity.

For example, q = cm δ t

(where q stands for heat, c stands for specific heat [capacity] of matter, m stands for mass of matter, and Δ t stands for temperature change).

Another example is f = k δ x (Hooke's law)

(where f stands for tension, k stands for spring stiffness coefficient, and δ x stands for spring elongation)

Any δ particle in particle physics

Extended data:

The Greek alphabet is used in mathematics, science, engineering and other fields.

In mathematics, Greek letters are usually used to represent constants, special functions and some specific variables. In the field of mathematics, the meanings of uppercase and lowercase Greek letters are usually different and irrelevant.

Some capitalized Greek letters are the same or very similar to the corresponding Latin letters, so they are not used, such as: A, B, E, H, I, K, M, N, O, P, T, X, Y, Z. In addition, lowercase ι(iota), ο(omicron) and μ (up

Sometimes, font variants of Greek letters have specific meanings in mathematics, such as φ(phi) and π(pi).

In financial mathematics, Greek letters are variables used to represent investment risks.

Mathematicians whose mother tongue is English don't read Greek letters with modern or ancient pronunciations, but read traditional English pronunciations. For example, the letter θ, these mathematicians will read it as [? θeit？ ]。 (In ancient times: [th^ε? Ta], nowadays: [? θita ])

Baidu Encyclopedia-δ (lowercase form of the fourth Greek letter δ)