Determinant of an n x n matrix
I do not know what this kind of matrix is called, it does not really look Circulant, but I tried to do many row and columns operation in order to make it into an upper triangular matrix so the determinant would be the product of the diagonal elements but I couldn't find a way. Any thoughts?
This is the matrix :
$$begin{bmatrix}n&n-1&n-2&cdots&2&1\1&n&n-1&cdots&3&2\1&1&n&cdots&4&3\vdots&vdots&vdots&ddots&vdots&vdots\1&1&1&cdots&n&n-1\1&1&1&cdots&1&lambdaend{bmatrix}$$
linear-algebra matrices determinant
add a comment |
I do not know what this kind of matrix is called, it does not really look Circulant, but I tried to do many row and columns operation in order to make it into an upper triangular matrix so the determinant would be the product of the diagonal elements but I couldn't find a way. Any thoughts?
This is the matrix :
$$begin{bmatrix}n&n-1&n-2&cdots&2&1\1&n&n-1&cdots&3&2\1&1&n&cdots&4&3\vdots&vdots&vdots&ddots&vdots&vdots\1&1&1&cdots&n&n-1\1&1&1&cdots&1&lambdaend{bmatrix}$$
linear-algebra matrices determinant
1
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08
add a comment |
I do not know what this kind of matrix is called, it does not really look Circulant, but I tried to do many row and columns operation in order to make it into an upper triangular matrix so the determinant would be the product of the diagonal elements but I couldn't find a way. Any thoughts?
This is the matrix :
$$begin{bmatrix}n&n-1&n-2&cdots&2&1\1&n&n-1&cdots&3&2\1&1&n&cdots&4&3\vdots&vdots&vdots&ddots&vdots&vdots\1&1&1&cdots&n&n-1\1&1&1&cdots&1&lambdaend{bmatrix}$$
linear-algebra matrices determinant
I do not know what this kind of matrix is called, it does not really look Circulant, but I tried to do many row and columns operation in order to make it into an upper triangular matrix so the determinant would be the product of the diagonal elements but I couldn't find a way. Any thoughts?
This is the matrix :
$$begin{bmatrix}n&n-1&n-2&cdots&2&1\1&n&n-1&cdots&3&2\1&1&n&cdots&4&3\vdots&vdots&vdots&ddots&vdots&vdots\1&1&1&cdots&n&n-1\1&1&1&cdots&1&lambdaend{bmatrix}$$
linear-algebra matrices determinant
linear-algebra matrices determinant
edited Dec 27 '18 at 13:44
StubbornAtom
5,34411138
5,34411138
asked Dec 27 '18 at 13:34
Paul Vinur
416
416
1
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08
add a comment |
1
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08
1
1
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08
add a comment |
2 Answers
2
active
oldest
votes
Let $M_n$ be your matrix.
Let $eta_n$ be the $ntimes n$ matrix with entry $1$ at the superdiagonal and $0$ 4 elsewhere. If you
Subtract row $k+1$ from row $k$ for $k = 1,2,ldots,n-1$.
This is equivalent to multiply $M_n$ by $I_n - eta_n$ from the leftSubtract column $k-1$ from column $k$ for $k = n,n-1,ldots,2$ (notice the order of $k$).
This is equivalent to multiply $(I_n-eta_n)M_n$ by $I_n - eta_n$ from the right.
After you do this, your matrix simplifies to
$$(I_n - eta_n) M_n (I_n - eta_n) =
begin{bmatrix}
n-1&-n&0&cdots&0&0&0\
0&n-1&-n&cdots&0&0&0\
0&0&n-1&ddots&0&0&0\
vdots&vdots&vdots&ddots&ddots&vdots&vdots\
0&0&0&cdots&n-1&-n&0\
0&0&0&cdots&0&n-1&-lambda\
1&0&0&cdots&0&0&lambda-1
end{bmatrix}$$
From this, you can deduce
$$det[M_n] = det[(I_n - eta_n)M_n(I_n - eta_n)]
= (n-1)^{n-1}(lambda-1) + n^{n-2}lambda$$
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
add a comment |
This is a rank one update of a triangular matrix. Let $A$ be the matrix in the post and let $B$ be the matrix with entries $b_{ij} = a_{ij} - 1$. Let $e$ be the column vector of 1's. Then $A = ee^T + B$.
Then $det(A) = det(B)(1+ e^TB^{-1}e)$. Since $B$ is triangular, $B^{-1}e$ is not hard to find.
This is defined if $lambda ne 1$. For $lambda = 1$, take the limit.
add a comment |
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
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3053935%2fdeterminant-of-an-n-x-n-matrix%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Let $M_n$ be your matrix.
Let $eta_n$ be the $ntimes n$ matrix with entry $1$ at the superdiagonal and $0$ 4 elsewhere. If you
Subtract row $k+1$ from row $k$ for $k = 1,2,ldots,n-1$.
This is equivalent to multiply $M_n$ by $I_n - eta_n$ from the leftSubtract column $k-1$ from column $k$ for $k = n,n-1,ldots,2$ (notice the order of $k$).
This is equivalent to multiply $(I_n-eta_n)M_n$ by $I_n - eta_n$ from the right.
After you do this, your matrix simplifies to
$$(I_n - eta_n) M_n (I_n - eta_n) =
begin{bmatrix}
n-1&-n&0&cdots&0&0&0\
0&n-1&-n&cdots&0&0&0\
0&0&n-1&ddots&0&0&0\
vdots&vdots&vdots&ddots&ddots&vdots&vdots\
0&0&0&cdots&n-1&-n&0\
0&0&0&cdots&0&n-1&-lambda\
1&0&0&cdots&0&0&lambda-1
end{bmatrix}$$
From this, you can deduce
$$det[M_n] = det[(I_n - eta_n)M_n(I_n - eta_n)]
= (n-1)^{n-1}(lambda-1) + n^{n-2}lambda$$
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
add a comment |
Let $M_n$ be your matrix.
Let $eta_n$ be the $ntimes n$ matrix with entry $1$ at the superdiagonal and $0$ 4 elsewhere. If you
Subtract row $k+1$ from row $k$ for $k = 1,2,ldots,n-1$.
This is equivalent to multiply $M_n$ by $I_n - eta_n$ from the leftSubtract column $k-1$ from column $k$ for $k = n,n-1,ldots,2$ (notice the order of $k$).
This is equivalent to multiply $(I_n-eta_n)M_n$ by $I_n - eta_n$ from the right.
After you do this, your matrix simplifies to
$$(I_n - eta_n) M_n (I_n - eta_n) =
begin{bmatrix}
n-1&-n&0&cdots&0&0&0\
0&n-1&-n&cdots&0&0&0\
0&0&n-1&ddots&0&0&0\
vdots&vdots&vdots&ddots&ddots&vdots&vdots\
0&0&0&cdots&n-1&-n&0\
0&0&0&cdots&0&n-1&-lambda\
1&0&0&cdots&0&0&lambda-1
end{bmatrix}$$
From this, you can deduce
$$det[M_n] = det[(I_n - eta_n)M_n(I_n - eta_n)]
= (n-1)^{n-1}(lambda-1) + n^{n-2}lambda$$
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
add a comment |
Let $M_n$ be your matrix.
Let $eta_n$ be the $ntimes n$ matrix with entry $1$ at the superdiagonal and $0$ 4 elsewhere. If you
Subtract row $k+1$ from row $k$ for $k = 1,2,ldots,n-1$.
This is equivalent to multiply $M_n$ by $I_n - eta_n$ from the leftSubtract column $k-1$ from column $k$ for $k = n,n-1,ldots,2$ (notice the order of $k$).
This is equivalent to multiply $(I_n-eta_n)M_n$ by $I_n - eta_n$ from the right.
After you do this, your matrix simplifies to
$$(I_n - eta_n) M_n (I_n - eta_n) =
begin{bmatrix}
n-1&-n&0&cdots&0&0&0\
0&n-1&-n&cdots&0&0&0\
0&0&n-1&ddots&0&0&0\
vdots&vdots&vdots&ddots&ddots&vdots&vdots\
0&0&0&cdots&n-1&-n&0\
0&0&0&cdots&0&n-1&-lambda\
1&0&0&cdots&0&0&lambda-1
end{bmatrix}$$
From this, you can deduce
$$det[M_n] = det[(I_n - eta_n)M_n(I_n - eta_n)]
= (n-1)^{n-1}(lambda-1) + n^{n-2}lambda$$
Let $M_n$ be your matrix.
Let $eta_n$ be the $ntimes n$ matrix with entry $1$ at the superdiagonal and $0$ 4 elsewhere. If you
Subtract row $k+1$ from row $k$ for $k = 1,2,ldots,n-1$.
This is equivalent to multiply $M_n$ by $I_n - eta_n$ from the leftSubtract column $k-1$ from column $k$ for $k = n,n-1,ldots,2$ (notice the order of $k$).
This is equivalent to multiply $(I_n-eta_n)M_n$ by $I_n - eta_n$ from the right.
After you do this, your matrix simplifies to
$$(I_n - eta_n) M_n (I_n - eta_n) =
begin{bmatrix}
n-1&-n&0&cdots&0&0&0\
0&n-1&-n&cdots&0&0&0\
0&0&n-1&ddots&0&0&0\
vdots&vdots&vdots&ddots&ddots&vdots&vdots\
0&0&0&cdots&n-1&-n&0\
0&0&0&cdots&0&n-1&-lambda\
1&0&0&cdots&0&0&lambda-1
end{bmatrix}$$
From this, you can deduce
$$det[M_n] = det[(I_n - eta_n)M_n(I_n - eta_n)]
= (n-1)^{n-1}(lambda-1) + n^{n-2}lambda$$
edited Dec 30 '18 at 9:54
Martin Sleziak
44.7k7115270
44.7k7115270
answered Dec 27 '18 at 16:20
achille hui
95.5k5130256
95.5k5130256
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
add a comment |
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
This is obviously the correct way since I checked the final answer. But the element "1" in the bottom left is still there and therefore not all elements (except diagonal and superdiagonal) are zeroes, and correct me if I am wrong, wouldn't that mean this is not a triangular matrix and we won't be able to find the det. by just multiplying the diagonal elements? And also I don't quite understand how we got (n^n-2 * λ)
– Paul Vinur
Dec 27 '18 at 17:07
2
2
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
@PaulVinur This is not a triangular matrix. Since the entries $a_{ij}$ vanishes unless $j = i text{ or } i+1 pmod n$. When you expand the determinant out completely, among all the $n!$ possible terms in the determinant, only two terms survive. i.e those of the form $prod_{i} a_{ii}$ and $prod_{} a_{i,i+1}$ ($i+1$ upto modulo $n$) survive. That's why the final expression is a sum of two terms.
– achille hui
Dec 27 '18 at 17:12
add a comment |
This is a rank one update of a triangular matrix. Let $A$ be the matrix in the post and let $B$ be the matrix with entries $b_{ij} = a_{ij} - 1$. Let $e$ be the column vector of 1's. Then $A = ee^T + B$.
Then $det(A) = det(B)(1+ e^TB^{-1}e)$. Since $B$ is triangular, $B^{-1}e$ is not hard to find.
This is defined if $lambda ne 1$. For $lambda = 1$, take the limit.
add a comment |
This is a rank one update of a triangular matrix. Let $A$ be the matrix in the post and let $B$ be the matrix with entries $b_{ij} = a_{ij} - 1$. Let $e$ be the column vector of 1's. Then $A = ee^T + B$.
Then $det(A) = det(B)(1+ e^TB^{-1}e)$. Since $B$ is triangular, $B^{-1}e$ is not hard to find.
This is defined if $lambda ne 1$. For $lambda = 1$, take the limit.
add a comment |
This is a rank one update of a triangular matrix. Let $A$ be the matrix in the post and let $B$ be the matrix with entries $b_{ij} = a_{ij} - 1$. Let $e$ be the column vector of 1's. Then $A = ee^T + B$.
Then $det(A) = det(B)(1+ e^TB^{-1}e)$. Since $B$ is triangular, $B^{-1}e$ is not hard to find.
This is defined if $lambda ne 1$. For $lambda = 1$, take the limit.
This is a rank one update of a triangular matrix. Let $A$ be the matrix in the post and let $B$ be the matrix with entries $b_{ij} = a_{ij} - 1$. Let $e$ be the column vector of 1's. Then $A = ee^T + B$.
Then $det(A) = det(B)(1+ e^TB^{-1}e)$. Since $B$ is triangular, $B^{-1}e$ is not hard to find.
This is defined if $lambda ne 1$. For $lambda = 1$, take the limit.
edited Dec 27 '18 at 19:39
answered Dec 27 '18 at 14:22
Hans Engler
10.1k11836
10.1k11836
add a comment |
add a comment |
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.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3053935%2fdeterminant-of-an-n-x-n-matrix%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
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
1
It is not clear what you need/want since you even didn't show us the matrix! Try to clarify your question.
– Sigur
Dec 27 '18 at 13:37
Do you have a particular matrix in mind, or just an arbitrary $n times n$ matrix?
– Clive Newstead
Dec 27 '18 at 13:37
I am sorry, the link to the picture was not included. I added it now.
– Paul Vinur
Dec 27 '18 at 13:41
Have you tried expanding over the first column or row for example or calculate the determinant for small values of $n$?
– Test123
Dec 27 '18 at 14:08