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. ∑ formula calculation: the number indicating the beginning and end. For example, the following n=2, and the number 10 above means from 2 to 10.

Example 1:

100

∑ n

n= 1

The formula "1+2+3+4+5+…+ 100" represents the sum of 1 00 consecutive natural numbers starting from1. Because the above formula is long and inconvenient to write, we can use "1+2" for simplicity.

Example 2:

10

∑2i

i=2

Expressions and formulas: (2 * 2)+(2 * 3)+(2 * 4)+...+(2 *10), that is, the sum of even numbers from 4 to 40.

Extended data:

Other symbols commonly used in mathematics

1, sign of quantity: for example, I, 2+i, A, X, natural logarithm base E, pi.

2. Operation symbols: such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (√), logarithm (log, lg, ln).

3. relational symbols: such as "=" is an equal sign, "≈" is an approximate sign, "≦" is an unequal sign and ">" is a greater than sign. "

4. Combination symbols: such as square brackets in brackets () and horizontal lines in braces ().

5. Natural symbols: such as positive sign "+",negative sign "-"and absolute value sign "∨".

References:

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