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. English name: Sima.
In physics, we use its lowercase letter σ to represent the area density. (Accordingly, ρ stands for bulk density and η stands for linear density).
Extended data:
Capital σ is used for mathematical summation symbols, such as ∑Pi, where i= 1, 2, ..., t, which is the sum of P 1+P2+ and ...+angle. Lowercase σ is used for statistical standard deviation. Both the с of Cyrillic alphabet and the S of Latin alphabet are derived from Sigma.
It also means summation, which means ∑ j = 1+2+3+…+n, where I stands for the lower bound, n stands for the upper bound, and k starts from I to n, and all of them are added up.
∑ Grade:
Analytic function of univalent function to single value in complex plane D region? (z), if there are any differences between d, z 1 and z2? (z 1)?？ (z2), then f(z) is called a univalent function on d.
Univalent function and its related univalent mapping are one of the most important research contents in the theory of complex variable functions. Univalent function has many good properties, such as: the most basic property of univalent function is that its derivative has no zero point; Univalent function or univalent function; Inverse function of univalent function or univalent function.
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