Xnn virtual currency
Publish: 2021-04-14 20:14:16
1. Let the random variable of head image upward be x1, and the random variable of head image downward be X2, then X1 = n - x2
then:
e (x1 - x2) = e (2x1 - n) = 2e (x1) - E (n) = 2np - n. If the parameter p = 1 / 2 is taken in, it will be 0, and it is expected to be 0
d (x1-x2) = D (2x1-n) = 4D (x1) - D (n) = 4NP (1-p). If P = 1 / 2, n is obtained, that is, the variance is n
the variance of binomial distribution is NP (1-p), and the variance of constant is 0.
then:
e (x1 - x2) = e (2x1 - n) = 2e (x1) - E (n) = 2np - n. If the parameter p = 1 / 2 is taken in, it will be 0, and it is expected to be 0
d (x1-x2) = D (2x1-n) = 4D (x1) - D (n) = 4NP (1-p). If P = 1 / 2, n is obtained, that is, the variance is n
the variance of binomial distribution is NP (1-p), and the variance of constant is 0.
2. '/ our-price\& quot;& gt;&# 92; u00A5 (.+)<&# 92;/ span>/&# 39;< br />
“\ "Unnnn" means "the character whose hexadecimal code is nnnn in Unicode code"
I checked the table, & yen; The Unicode code is 00a5 in hexadecimal, so it can be like this
I have tested it, and it will be OK; A alarm character (the effect of printing it is that the computer beeps)
& # 92; B is usually the word boundary position, but if it is used in character class to represent backspace
& # 92; T tab, tab
& # 92; R enter
\ V vertical tab
& # 92; F page break
& # 92; N newline character
\ e Escape
\ 0nn characters with octal code of NN in ASCII code
\ In xnn ASCII code, the characters whose hexadecimal code is NN
\ The characters whose hexadecimal code is nnnn in unnnn Unicode code
\ Cn ASCII control character. For example, &92; CC stands for Ctrl + C
& # 92; The beginning of a string (similar to ^, but not affected by the option of processing multiple lines)
& # 92; The end of Z string or the end of line (not affected by the option of processing multiple lines)
\ The end of the Z string (similar to $, but not affected by the option of processing multiple lines)
\ G the beginning of the current search
& # 92; The character class named name in P {name} Unicode, such as & # 92; p{IsGreek}
(?& gt; Exp) greedy subexpression
(& lt; x>-& lt; y> Exp) balance group
(? im- nsx:exp Change the processing options in the sub expression exp
(? Im NSX) changes the processing options for the part after the expression
( Exp) yes | no) takes exp as a zero width forward antecedent assertion. If it can match at this position, yes is used as the expression of this group; Otherwise, no
( Exp) yes) the same as above, only using empty expression as no
( Name) yes | no) if the group named name captures the content, use yes as the expression; Otherwise, no
( Name) yes) the same as above, but use empty expression as No
“\ "Unnnn" means "the character whose hexadecimal code is nnnn in Unicode code"
I checked the table, & yen; The Unicode code is 00a5 in hexadecimal, so it can be like this
I have tested it, and it will be OK; A alarm character (the effect of printing it is that the computer beeps)
& # 92; B is usually the word boundary position, but if it is used in character class to represent backspace
& # 92; T tab, tab
& # 92; R enter
\ V vertical tab
& # 92; F page break
& # 92; N newline character
\ e Escape
\ 0nn characters with octal code of NN in ASCII code
\ In xnn ASCII code, the characters whose hexadecimal code is NN
\ The characters whose hexadecimal code is nnnn in unnnn Unicode code
\ Cn ASCII control character. For example, &92; CC stands for Ctrl + C
& # 92; The beginning of a string (similar to ^, but not affected by the option of processing multiple lines)
& # 92; The end of Z string or the end of line (not affected by the option of processing multiple lines)
\ The end of the Z string (similar to $, but not affected by the option of processing multiple lines)
\ G the beginning of the current search
& # 92; The character class named name in P {name} Unicode, such as & # 92; p{IsGreek}
(?& gt; Exp) greedy subexpression
(& lt; x>-& lt; y> Exp) balance group
(? im- nsx:exp Change the processing options in the sub expression exp
(? Im NSX) changes the processing options for the part after the expression
( Exp) yes | no) takes exp as a zero width forward antecedent assertion. If it can match at this position, yes is used as the expression of this group; Otherwise, no
( Exp) yes) the same as above, only using empty expression as no
( Name) yes | no) if the group named name captures the content, use yes as the expression; Otherwise, no
( Name) yes) the same as above, but use empty expression as No
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