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anonymous
 one year ago
Is there an ISBN that has the form : x  315266782?
anonymous
 one year ago
Is there an ISBN that has the form : x  315266782?

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0This question I have right now in my math course, we've had null information about how to do it? could anyone explain to me how to?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@IrishBoy123 you know anything bout this?

IrishBoy123
 one year ago
Best ResponseYou've already chosen the best response.1ISBN is something to do with books and unique ID numbers and that is everything i know, assuming it is actually correct :)

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1I don't see how this is a question, ISBN's are on the back of your book, is it asking you to get a book with the certain ISBN maybe?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@Astrophysics no, you are suppose to show with math calculation if it is a true ISBN or not!

Astrophysics
 one year ago
Best ResponseYou've already chosen the best response.1Oh, I have no idea then, sorry :\

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0It has to do with somekind of sequence, and congruity

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0we are studying residue class arithmetic or what it is called in english

perl
 one year ago
Best ResponseYou've already chosen the best response.1Here is an example ISBN numbers for published books. The ISBN number for our textbook is 0131848682. The information is decoded in the first 9 digits. The last digit is for parity check 1 * a1 + 2 * a2 + ... + 9 * a9 = a10 Applying this to our textbook 1 * 0 + 2 * 1 + 3 * 3 + 4 * 1 + 5 * 8 + 6 * 4 + 7 * 8 + 8 * 6 + 9 * 8 = 255 = 2 mod 11 The sum of 9 digits is 255 and it equals to the last digit mod 11.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0⇒ a10 = 4 eftersom 11  103 + 40 = 143 \[a _{1}, a _{2}, a _{3}, ..., a _{10}\] the numbers in ISBN \[a _{10}\] is choosen like: \[a _{1}+ 2a _{2}+ 3a _{3}+ ..., 9a _{9}+10a_{10}≡ 0 (mod 11)\] if \[a_{10}=10\] you write X Example ISBN=093603103a10 \[a_{10}\] is choosen like \[1 · 0 + 2 · 9 + 3 · 3 + · · · + 9 · 3 + 10 · a_{10} = 103 + 10a_{10} ≡ 0 (mod 11)\] ⇒ \[a_{10} = 4 \] because \[11  103 + 40 = 143\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ah wait I gotta write this down and see

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so here I got x+226=2 (mod10)?

perl
 one year ago
Best ResponseYou've already chosen the best response.1so we need to check that x  315266782 can be an isbn number, only if 1*x + 2*3 + 3*1 + 4*5 + 5*2 + 6 * 6 + 7*6 + 8*7 + 9*8 = 2 mod 11

perl
 one year ago
Best ResponseYou've already chosen the best response.1check again, I got x + 245 = 2 mod 11

perl
 one year ago
Best ResponseYou've already chosen the best response.11*x + 2*3 + 3*1 + 4*5 + 5*2 + 6 * 6 + 7*6 + 8*7 + 9*8 = x + 245

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yea.. i got the same

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so then should x+245/11 give something with the rest 2..

perl
 one year ago
Best ResponseYou've already chosen the best response.1x + 245 = 2 mod 11 x = 2  245 mod 11 x = 243 mod 11 x = 10 mod 11

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0can you explain the last step?

perl
 one year ago
Best ResponseYou've already chosen the best response.1but notice that 10 is not a choice for an isbn digit, since it has to be a digit from 0 to 9 so the answer is, there is no x

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i mean from 243 to 10 mod 11

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yeah but how did you make 243 mod 11 to 10 mod 11?

perl
 one year ago
Best ResponseYou've already chosen the best response.1it is easier to use multiple of 11's

perl
 one year ago
Best ResponseYou've already chosen the best response.1I am actually using my calculator for negative mod

perl
 one year ago
Best ResponseYou've already chosen the best response.1x + 245 = 2 mod 11 with respect to 245 where is the closest multiple of 11 ?

perl
 one year ago
Best ResponseYou've already chosen the best response.1245 = 3 mod 11 , so we can substitute (x + 245) mod 11 = (x + 3) mod 11 now solve (x+3) mod 11 = 2 mod 11 x = 23 mod 11 x = 1 mod 11

perl
 one year ago
Best ResponseYou've already chosen the best response.1when you do negative integers, it is like going backwards with a clock

perl
 one year ago
Best ResponseYou've already chosen the best response.10 mod 11 = 11 mod 11 1 mod 11 = 10 mod 11 2 mod 11 = 9 mod 11 3 mod 11 = 8 mod 11

perl
 one year ago
Best ResponseYou've already chosen the best response.1imagine we have an 11 hour clock

perl
 one year ago
Best ResponseYou've already chosen the best response.11 aclock = 10 aclock mod 11 2 aclock = 9 aclock mod 11 , etc

perl
 one year ago
Best ResponseYou've already chosen the best response.1also because 1 mod 11 = (1 + 11 ) mod 11 = 10 mod 11

perl
 one year ago
Best ResponseYou've already chosen the best response.1thats the easiest way to see it. or you can use definition of mod a = b mod n iff b a is divisible by n 1 = 10 mod because 10 (1) is divisible by 11

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I got it perl:D thanks alot, but the answear is it isnt a ISBN just because it have to be a integer between 1 and 9?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0between 0 and 9 i mean

perl
 one year ago
Best ResponseYou've already chosen the best response.1the answer is, there is no such ISBN, since the only way it would work is if x = 10 but the possible choices for x is 0  9 .

perl
 one year ago
Best ResponseYou've already chosen the best response.1the only way the total x + 245 can equal 2 mod 11 is if x is 10. but that is not possible for the isbn, x must be integer 0 through 9

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@perl thanks alot! :D
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