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How to use symbols
1, usage:

For example, "i= 1" can be written below the symbol, and "n" can be written above it, which means that I in the following quadrature formula is added to n from 1.

That is, (1+d1/p1) (1+d2/p2) ... (1+dn/pn).

2. Greek letters:

① ∏ is the Greek letter, that is, the capitalized form of π, which mathematically means quadrature operation or direct product operation, and is similar to σ in form.

② Lowercase: π

In mathematics, pi is often mentioned. Pi, generally expressed by π, is a common mathematical constant in mathematics and physics. It is defined as the ratio of the circumference to the diameter of a circle. It is also equal to the ratio of the area of a circle to the square of its radius.

Accurate calculation of geometric shapes such as circle perimeter, circle area and sphere volume is the key value. In the analysis, π can be strictly defined as the smallest positive real number x satisfying sin(x) = 0.

Constant pi ≈3. 14 Preliminary calculation of Zu Chongzhi (China) 3. 14 15926

Extended data:

?

Mathematical permutation and combination symbols

c? Number of combinations

A (or p)? number of permutations

n? Total number of elements

r? Number of elements participating in the selection

Factorial, such as 5! =5×4×3×2× 1= 120, specify 0! = 1

Half factorial (also called double factorial), for example, 7! ! =7×5×3× 1= 105, 10! ! = 10×8×6×4×2=3840

σ addition

Discrete mathematical symbol

Universal quantifier

Existential quantifier

├ determinant (formula can be proved by L)

Satisfier (formula is valid on e, and formula can be satisfied on e)

The negation of a proposition, such as the negation of a proposition is ﹁ P.

∧ "He" ("And") Operation of Proposition

The "disjunctive" ("or", "combinable or") operation of propositions

"Conditional" Operation of Proposition

"Double Condition" Operation of Proposition

p & lt= & gtq? Equivalence relation between propositions p and q

p = & gtq? Implication relation between proposition P and Q (P is a sufficient condition for Q, and Q is a necessary condition for P)

A* the dual formula of formula A, or the reciprocal of number theory (can also be written as

)

wff? Combination formula

iff? The only possibility is that

"NAND" operation of proposition ("NAND gate")

The nor operation of a proposition (nor gate)

□? The modal particle "inevitable"

The modal particle "may"

null set

Belong to (such as "A∈B", that is, "A belongs to B")

Do not belong to

Power set of P(A) set a

The number of points in set a

r? =R○R [R

Baidu Encyclopedia-π (Greek alphabet)