The ∑ symbol means sum, and the ∑ pronunciation is sigma, which means sum and sum in English.
The method of summing with sigma is called Sigma Notation.
The usage expression of ∑ is as follows:
Where I stands for the lower bound, n stands for the upper bound, and k starts from I and goes all the way to n, all of which add up.
∑ i can also be expressed as the sum of I, which is a variable.
Extended data:
∑ is the eighteenth Greek letter. In Greek, if the last letter of a word is lowercase sigma, what should it be written as? This letter is also called final sigma(Unicode: U+03C2). In modern Greece, this number stands for 6.
Its lowercase is σ, which is often used in physics to represent the area density. (Therefore, ρ stands for bulk density and η stands for linear density)
The term σ is used to describe the distribution or dispersion of the average value of any process parameter.
Chemically, surface tension (σ)(sigma) refers to the force that molecules on the surface of a liquid shrink inward to the smallest area.
Chemically, it also refers to the σ bond formed by two electron clouds "head to head" along the orbital axis.
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