If real Matrix A is symmetric and positive definite then $X^TAY $ represent dot product with respect to basis...












1















If real Matrix A is symmetric and positive definite then $X^TAY $ represent dot product with respect to basis of $mathbb R^n$




I am studying now bilinear form .I wanted to prove above theorem.



I know that for bilinear for to represent dot product It's matrix is of form $P^TP$
which provide reverse direction.



I not able to prove forword direction.
Any hint will be appreciated










share|cite|improve this question






















  • $<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
    – Yadati Kiran
    Nov 25 at 7:01
















1















If real Matrix A is symmetric and positive definite then $X^TAY $ represent dot product with respect to basis of $mathbb R^n$




I am studying now bilinear form .I wanted to prove above theorem.



I know that for bilinear for to represent dot product It's matrix is of form $P^TP$
which provide reverse direction.



I not able to prove forword direction.
Any hint will be appreciated










share|cite|improve this question






















  • $<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
    – Yadati Kiran
    Nov 25 at 7:01














1












1








1








If real Matrix A is symmetric and positive definite then $X^TAY $ represent dot product with respect to basis of $mathbb R^n$




I am studying now bilinear form .I wanted to prove above theorem.



I know that for bilinear for to represent dot product It's matrix is of form $P^TP$
which provide reverse direction.



I not able to prove forword direction.
Any hint will be appreciated










share|cite|improve this question














If real Matrix A is symmetric and positive definite then $X^TAY $ represent dot product with respect to basis of $mathbb R^n$




I am studying now bilinear form .I wanted to prove above theorem.



I know that for bilinear for to represent dot product It's matrix is of form $P^TP$
which provide reverse direction.



I not able to prove forword direction.
Any hint will be appreciated







linear-algebra positive-definite bilinear-form symmetric-matrices






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 25 at 6:09









MathLover

45710




45710












  • $<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
    – Yadati Kiran
    Nov 25 at 7:01


















  • $<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
    – Yadati Kiran
    Nov 25 at 7:01
















$<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
– Yadati Kiran
Nov 25 at 7:01




$<X,Y>=X^TAY$. What should $<cdot,cdot>$ satisfy?
– Yadati Kiran
Nov 25 at 7:01










1 Answer
1






active

oldest

votes


















1














Hint: You must show





  • $langle X,Xranglegeq 0$ and $langle X,Xrangle= 0 iff X=0$

  • $langle X,Yrangle=langle Y,Xrangle$


  • $langle X+Y,Z rangle=langle X,Zrangle+langle Y,Xrangle$ and $langle alpha X,Yrangle=alphalangle X,Yrangle,quadalphainmathbb{R}^n$.






share|cite|improve this answer





















  • As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
    – Yadati Kiran
    Nov 25 at 15:48













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',
autoActivateHeartbeat: false,
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%2f3012487%2fif-real-matrix-a-is-symmetric-and-positive-definite-then-xtay-represent-dot%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









1














Hint: You must show





  • $langle X,Xranglegeq 0$ and $langle X,Xrangle= 0 iff X=0$

  • $langle X,Yrangle=langle Y,Xrangle$


  • $langle X+Y,Z rangle=langle X,Zrangle+langle Y,Xrangle$ and $langle alpha X,Yrangle=alphalangle X,Yrangle,quadalphainmathbb{R}^n$.






share|cite|improve this answer





















  • As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
    – Yadati Kiran
    Nov 25 at 15:48


















1














Hint: You must show





  • $langle X,Xranglegeq 0$ and $langle X,Xrangle= 0 iff X=0$

  • $langle X,Yrangle=langle Y,Xrangle$


  • $langle X+Y,Z rangle=langle X,Zrangle+langle Y,Xrangle$ and $langle alpha X,Yrangle=alphalangle X,Yrangle,quadalphainmathbb{R}^n$.






share|cite|improve this answer





















  • As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
    – Yadati Kiran
    Nov 25 at 15:48
















1












1








1






Hint: You must show





  • $langle X,Xranglegeq 0$ and $langle X,Xrangle= 0 iff X=0$

  • $langle X,Yrangle=langle Y,Xrangle$


  • $langle X+Y,Z rangle=langle X,Zrangle+langle Y,Xrangle$ and $langle alpha X,Yrangle=alphalangle X,Yrangle,quadalphainmathbb{R}^n$.






share|cite|improve this answer












Hint: You must show





  • $langle X,Xranglegeq 0$ and $langle X,Xrangle= 0 iff X=0$

  • $langle X,Yrangle=langle Y,Xrangle$


  • $langle X+Y,Z rangle=langle X,Zrangle+langle Y,Xrangle$ and $langle alpha X,Yrangle=alphalangle X,Yrangle,quadalphainmathbb{R}^n$.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Nov 25 at 7:08









Yadati Kiran

1,694519




1,694519












  • As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
    – Yadati Kiran
    Nov 25 at 15:48




















  • As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
    – Yadati Kiran
    Nov 25 at 15:48


















As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
– Yadati Kiran
Nov 25 at 15:48






As an exercise you can try "If the dot product in $mathbb{R}^n$ is defined as $langle X,Yrangle=X^TAY$, then A is symmetric and positive definite.$ "
– Yadati Kiran
Nov 25 at 15:48




















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3012487%2fif-real-matrix-a-is-symmetric-and-positive-definite-then-xtay-represent-dot%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

Ellipse (mathématiques)

Quarter-circle Tiles

Mont Emei