Neutral Element on $(mathbb{C},*,+)$











up vote
0
down vote

favorite












I want to show the neutral Element on $$(mathbb{C},*,+)$$



Let the complex Number be defined as:
$$(x,y)$$
Multiplication of complex numbers is defined as:
$$(x_{1}, y_{1}) * (x_{2}, y_{2}):= (x_{1}x_{2}-y_{1}y_{2}, x_{1}y_{2}+x_{2}y_{1})$$
By definition the neutral element is:
$$(e_{x}, e_{y}) *(x,y) = (x,y)$$
$$(x*e_{x}-y*e_{y}, x*e_{y}+y*e_{x})$$
This gives an equation system:
$$x = x*e_{x} -y*e_{y}$$
$$y = x*e_{y} +y*e_{x}$$



Is this the correct approach to finding the neutral Element?



If yes, what is the correct method for solving the equation system?










share|cite|improve this question
























  • Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
    – Paul Frost
    23 hours ago










  • I want to show how to get to the value (1,0)
    – Thomas Christopher Davies
    19 hours ago










  • Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
    – Paul Frost
    19 hours ago










  • I don't see this being a good derivation
    – Thomas Christopher Davies
    18 hours ago















up vote
0
down vote

favorite












I want to show the neutral Element on $$(mathbb{C},*,+)$$



Let the complex Number be defined as:
$$(x,y)$$
Multiplication of complex numbers is defined as:
$$(x_{1}, y_{1}) * (x_{2}, y_{2}):= (x_{1}x_{2}-y_{1}y_{2}, x_{1}y_{2}+x_{2}y_{1})$$
By definition the neutral element is:
$$(e_{x}, e_{y}) *(x,y) = (x,y)$$
$$(x*e_{x}-y*e_{y}, x*e_{y}+y*e_{x})$$
This gives an equation system:
$$x = x*e_{x} -y*e_{y}$$
$$y = x*e_{y} +y*e_{x}$$



Is this the correct approach to finding the neutral Element?



If yes, what is the correct method for solving the equation system?










share|cite|improve this question
























  • Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
    – Paul Frost
    23 hours ago










  • I want to show how to get to the value (1,0)
    – Thomas Christopher Davies
    19 hours ago










  • Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
    – Paul Frost
    19 hours ago










  • I don't see this being a good derivation
    – Thomas Christopher Davies
    18 hours ago













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I want to show the neutral Element on $$(mathbb{C},*,+)$$



Let the complex Number be defined as:
$$(x,y)$$
Multiplication of complex numbers is defined as:
$$(x_{1}, y_{1}) * (x_{2}, y_{2}):= (x_{1}x_{2}-y_{1}y_{2}, x_{1}y_{2}+x_{2}y_{1})$$
By definition the neutral element is:
$$(e_{x}, e_{y}) *(x,y) = (x,y)$$
$$(x*e_{x}-y*e_{y}, x*e_{y}+y*e_{x})$$
This gives an equation system:
$$x = x*e_{x} -y*e_{y}$$
$$y = x*e_{y} +y*e_{x}$$



Is this the correct approach to finding the neutral Element?



If yes, what is the correct method for solving the equation system?










share|cite|improve this question















I want to show the neutral Element on $$(mathbb{C},*,+)$$



Let the complex Number be defined as:
$$(x,y)$$
Multiplication of complex numbers is defined as:
$$(x_{1}, y_{1}) * (x_{2}, y_{2}):= (x_{1}x_{2}-y_{1}y_{2}, x_{1}y_{2}+x_{2}y_{1})$$
By definition the neutral element is:
$$(e_{x}, e_{y}) *(x,y) = (x,y)$$
$$(x*e_{x}-y*e_{y}, x*e_{y}+y*e_{x})$$
This gives an equation system:
$$x = x*e_{x} -y*e_{y}$$
$$y = x*e_{y} +y*e_{x}$$



Is this the correct approach to finding the neutral Element?



If yes, what is the correct method for solving the equation system?







complex-numbers systems-of-equations






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited 23 hours ago









Cameron Buie

84.4k771155




84.4k771155










asked 23 hours ago









Thomas Christopher Davies

247




247












  • Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
    – Paul Frost
    23 hours ago










  • I want to show how to get to the value (1,0)
    – Thomas Christopher Davies
    19 hours ago










  • Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
    – Paul Frost
    19 hours ago










  • I don't see this being a good derivation
    – Thomas Christopher Davies
    18 hours ago


















  • Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
    – Paul Frost
    23 hours ago










  • I want to show how to get to the value (1,0)
    – Thomas Christopher Davies
    19 hours ago










  • Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
    – Paul Frost
    19 hours ago










  • I don't see this being a good derivation
    – Thomas Christopher Davies
    18 hours ago
















Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
– Paul Frost
23 hours ago




Of course you can determine the multplicative neutral element by solving the above equation system. But I am sure you already know that the neutral element is $(1,0)$, and in that case it suffices to verify the equation $(1,0) * (x,y) = (x,y)$.
– Paul Frost
23 hours ago












I want to show how to get to the value (1,0)
– Thomas Christopher Davies
19 hours ago




I want to show how to get to the value (1,0)
– Thomas Christopher Davies
19 hours ago












Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
– Paul Frost
19 hours ago




Then simply note that you must have $(e_x,e_y) * (1,0) = (1,0)$. This gives you $1 = e_x$ and $0 = e_y$.
– Paul Frost
19 hours ago












I don't see this being a good derivation
– Thomas Christopher Davies
18 hours ago




I don't see this being a good derivation
– Thomas Christopher Davies
18 hours ago










1 Answer
1






active

oldest

votes

















up vote
2
down vote













Your approach is not (quite) correct because you should have $x=xe_x-ye_y$ and $y=xe_y+ye_x$ (just normal multiplication instead of your "*" operation). Also, the equations should hold for any x and y in $mathbb{C}$ and this implies that $e_x=1$ and $e_y=0$






share|cite|improve this answer





















  • But how can I show it?
    – Thomas Christopher Davies
    19 hours ago










  • @Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
    – Sorin Tirc
    15 hours ago













Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














 

draft saved


draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3004861%2fneutral-element-on-mathbbc%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
2
down vote













Your approach is not (quite) correct because you should have $x=xe_x-ye_y$ and $y=xe_y+ye_x$ (just normal multiplication instead of your "*" operation). Also, the equations should hold for any x and y in $mathbb{C}$ and this implies that $e_x=1$ and $e_y=0$






share|cite|improve this answer





















  • But how can I show it?
    – Thomas Christopher Davies
    19 hours ago










  • @Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
    – Sorin Tirc
    15 hours ago

















up vote
2
down vote













Your approach is not (quite) correct because you should have $x=xe_x-ye_y$ and $y=xe_y+ye_x$ (just normal multiplication instead of your "*" operation). Also, the equations should hold for any x and y in $mathbb{C}$ and this implies that $e_x=1$ and $e_y=0$






share|cite|improve this answer





















  • But how can I show it?
    – Thomas Christopher Davies
    19 hours ago










  • @Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
    – Sorin Tirc
    15 hours ago















up vote
2
down vote










up vote
2
down vote









Your approach is not (quite) correct because you should have $x=xe_x-ye_y$ and $y=xe_y+ye_x$ (just normal multiplication instead of your "*" operation). Also, the equations should hold for any x and y in $mathbb{C}$ and this implies that $e_x=1$ and $e_y=0$






share|cite|improve this answer












Your approach is not (quite) correct because you should have $x=xe_x-ye_y$ and $y=xe_y+ye_x$ (just normal multiplication instead of your "*" operation). Also, the equations should hold for any x and y in $mathbb{C}$ and this implies that $e_x=1$ and $e_y=0$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered 23 hours ago









Sorin Tirc

4888




4888












  • But how can I show it?
    – Thomas Christopher Davies
    19 hours ago










  • @Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
    – Sorin Tirc
    15 hours ago




















  • But how can I show it?
    – Thomas Christopher Davies
    19 hours ago










  • @Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
    – Sorin Tirc
    15 hours ago


















But how can I show it?
– Thomas Christopher Davies
19 hours ago




But how can I show it?
– Thomas Christopher Davies
19 hours ago












@Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
– Sorin Tirc
15 hours ago






@Thomas Cristopher Davies : Your mistake is that you are confusing “” with the normal multiplication between two real numbers. Your operation is defined so that ($e_x,e_y$)(x,y)= ($e_xx-e_yy,e_xy+e_yx$) and NOT as ($e_x,e_y$)(x,y)= ($e_x*x-e_y*y,e_x*y+e_y*x$). It wouldn’t even make sens for “” to be defined in terms of itself...by the way, “*” is just complex multiplication
– Sorin Tirc
15 hours ago




















 

draft saved


draft discarded



















































 


draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3004861%2fneutral-element-on-mathbbc%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

'app-layout' is not a known element: how to share Component with different Modules

android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

WPF add header to Image with URL pettitions [duplicate]