How to Show that $[2]_6$ and $[3]_9$ are disjoint
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I’m not sure how to prove this. Specifically, I don’t fully understand congruence class modulo m to prove these sets are disjoint.
elementary-set-theory proof-writing proof-explanation
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add a comment |
$begingroup$
I’m not sure how to prove this. Specifically, I don’t fully understand congruence class modulo m to prove these sets are disjoint.
elementary-set-theory proof-writing proof-explanation
$endgroup$
add a comment |
$begingroup$
I’m not sure how to prove this. Specifically, I don’t fully understand congruence class modulo m to prove these sets are disjoint.
elementary-set-theory proof-writing proof-explanation
$endgroup$
I’m not sure how to prove this. Specifically, I don’t fully understand congruence class modulo m to prove these sets are disjoint.
elementary-set-theory proof-writing proof-explanation
elementary-set-theory proof-writing proof-explanation
edited Dec 2 '18 at 1:55
darylnak
asked Dec 2 '18 at 1:43
darylnakdarylnak
169111
169111
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4 Answers
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Hint $ 3 + 9x = 2+6y iff color{#c00}1 = 6y-9x = color{#c00}3(2y-3x)$
Or $ nequiv 2pmod{!6},Rightarrow, nequiv color{#0a0}2pmod{!3} $ by $ 2+6j = 2+3(2j)$
but $, nequiv 3pmod{!9},Rightarrow, nequiv color{#0a0}3pmod{!3}$
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add a comment |
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$[2]_6$ is the set of all integers which have $2$ as remainder when divided by $6$, and $[3]_9$ is the set of all integers which have $3$ as remainder when divided by $9$. So an integer $x$ in both congruence classes could be written as
$$x=2+6k=3+9ell$$
which implies $$3-2=1=6k-9ell.$$
Can you why there is a problem?
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There was an error in my question. It should have been [3]_9
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– darylnak
Dec 2 '18 at 1:55
add a comment |
$begingroup$
You can think of the congruence class modulo $m$ to be the set of numbers with remainder $n$ when divided by $m$ (where $n<m$).
Once you have that, no integer can have two different remainders, then it must be in at most one of these sets, maybe neither.
$endgroup$
add a comment |
$begingroup$
If I understand your notation, $[2]_6$ consists of all the numbers congruent to $2$ modulo $6$. Those are the numbers that leave a remainder of $2$ when you divide by $6$, so
$$
[2]_6 = { ldots , -10, -4, 2, 8, 14, ldots}.
$$
Can you finish now? Write down $[3]_6$ and check whether it and ${2}_6$ have any numbers in common.
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There was an error in my question. It should have been [3]_9
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– darylnak
Dec 2 '18 at 1:56
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Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
add a comment |
Your Answer
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Hint $ 3 + 9x = 2+6y iff color{#c00}1 = 6y-9x = color{#c00}3(2y-3x)$
Or $ nequiv 2pmod{!6},Rightarrow, nequiv color{#0a0}2pmod{!3} $ by $ 2+6j = 2+3(2j)$
but $, nequiv 3pmod{!9},Rightarrow, nequiv color{#0a0}3pmod{!3}$
$endgroup$
add a comment |
$begingroup$
Hint $ 3 + 9x = 2+6y iff color{#c00}1 = 6y-9x = color{#c00}3(2y-3x)$
Or $ nequiv 2pmod{!6},Rightarrow, nequiv color{#0a0}2pmod{!3} $ by $ 2+6j = 2+3(2j)$
but $, nequiv 3pmod{!9},Rightarrow, nequiv color{#0a0}3pmod{!3}$
$endgroup$
add a comment |
$begingroup$
Hint $ 3 + 9x = 2+6y iff color{#c00}1 = 6y-9x = color{#c00}3(2y-3x)$
Or $ nequiv 2pmod{!6},Rightarrow, nequiv color{#0a0}2pmod{!3} $ by $ 2+6j = 2+3(2j)$
but $, nequiv 3pmod{!9},Rightarrow, nequiv color{#0a0}3pmod{!3}$
$endgroup$
Hint $ 3 + 9x = 2+6y iff color{#c00}1 = 6y-9x = color{#c00}3(2y-3x)$
Or $ nequiv 2pmod{!6},Rightarrow, nequiv color{#0a0}2pmod{!3} $ by $ 2+6j = 2+3(2j)$
but $, nequiv 3pmod{!9},Rightarrow, nequiv color{#0a0}3pmod{!3}$
edited Dec 2 '18 at 2:14
answered Dec 2 '18 at 2:05
Bill DubuqueBill Dubuque
211k29192645
211k29192645
add a comment |
add a comment |
$begingroup$
$[2]_6$ is the set of all integers which have $2$ as remainder when divided by $6$, and $[3]_9$ is the set of all integers which have $3$ as remainder when divided by $9$. So an integer $x$ in both congruence classes could be written as
$$x=2+6k=3+9ell$$
which implies $$3-2=1=6k-9ell.$$
Can you why there is a problem?
$endgroup$
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
add a comment |
$begingroup$
$[2]_6$ is the set of all integers which have $2$ as remainder when divided by $6$, and $[3]_9$ is the set of all integers which have $3$ as remainder when divided by $9$. So an integer $x$ in both congruence classes could be written as
$$x=2+6k=3+9ell$$
which implies $$3-2=1=6k-9ell.$$
Can you why there is a problem?
$endgroup$
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
add a comment |
$begingroup$
$[2]_6$ is the set of all integers which have $2$ as remainder when divided by $6$, and $[3]_9$ is the set of all integers which have $3$ as remainder when divided by $9$. So an integer $x$ in both congruence classes could be written as
$$x=2+6k=3+9ell$$
which implies $$3-2=1=6k-9ell.$$
Can you why there is a problem?
$endgroup$
$[2]_6$ is the set of all integers which have $2$ as remainder when divided by $6$, and $[3]_9$ is the set of all integers which have $3$ as remainder when divided by $9$. So an integer $x$ in both congruence classes could be written as
$$x=2+6k=3+9ell$$
which implies $$3-2=1=6k-9ell.$$
Can you why there is a problem?
edited Dec 2 '18 at 2:04
answered Dec 2 '18 at 1:51
BernardBernard
121k740116
121k740116
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
add a comment |
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:55
add a comment |
$begingroup$
You can think of the congruence class modulo $m$ to be the set of numbers with remainder $n$ when divided by $m$ (where $n<m$).
Once you have that, no integer can have two different remainders, then it must be in at most one of these sets, maybe neither.
$endgroup$
add a comment |
$begingroup$
You can think of the congruence class modulo $m$ to be the set of numbers with remainder $n$ when divided by $m$ (where $n<m$).
Once you have that, no integer can have two different remainders, then it must be in at most one of these sets, maybe neither.
$endgroup$
add a comment |
$begingroup$
You can think of the congruence class modulo $m$ to be the set of numbers with remainder $n$ when divided by $m$ (where $n<m$).
Once you have that, no integer can have two different remainders, then it must be in at most one of these sets, maybe neither.
$endgroup$
You can think of the congruence class modulo $m$ to be the set of numbers with remainder $n$ when divided by $m$ (where $n<m$).
Once you have that, no integer can have two different remainders, then it must be in at most one of these sets, maybe neither.
answered Dec 2 '18 at 1:49
NL1992NL1992
7311
7311
add a comment |
add a comment |
$begingroup$
If I understand your notation, $[2]_6$ consists of all the numbers congruent to $2$ modulo $6$. Those are the numbers that leave a remainder of $2$ when you divide by $6$, so
$$
[2]_6 = { ldots , -10, -4, 2, 8, 14, ldots}.
$$
Can you finish now? Write down $[3]_6$ and check whether it and ${2}_6$ have any numbers in common.
$endgroup$
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
add a comment |
$begingroup$
If I understand your notation, $[2]_6$ consists of all the numbers congruent to $2$ modulo $6$. Those are the numbers that leave a remainder of $2$ when you divide by $6$, so
$$
[2]_6 = { ldots , -10, -4, 2, 8, 14, ldots}.
$$
Can you finish now? Write down $[3]_6$ and check whether it and ${2}_6$ have any numbers in common.
$endgroup$
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
add a comment |
$begingroup$
If I understand your notation, $[2]_6$ consists of all the numbers congruent to $2$ modulo $6$. Those are the numbers that leave a remainder of $2$ when you divide by $6$, so
$$
[2]_6 = { ldots , -10, -4, 2, 8, 14, ldots}.
$$
Can you finish now? Write down $[3]_6$ and check whether it and ${2}_6$ have any numbers in common.
$endgroup$
If I understand your notation, $[2]_6$ consists of all the numbers congruent to $2$ modulo $6$. Those are the numbers that leave a remainder of $2$ when you divide by $6$, so
$$
[2]_6 = { ldots , -10, -4, 2, 8, 14, ldots}.
$$
Can you finish now? Write down $[3]_6$ and check whether it and ${2}_6$ have any numbers in common.
answered Dec 2 '18 at 1:48
Ethan BolkerEthan Bolker
43.4k551116
43.4k551116
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
add a comment |
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
There was an error in my question. It should have been [3]_9
$endgroup$
– darylnak
Dec 2 '18 at 1:56
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
$begingroup$
Well write that one down and see if it overlaps $[2]_6$.
$endgroup$
– Ethan Bolker
Dec 2 '18 at 2:19
add a comment |
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