symbolic – High-order Differential Equation

I need help in solving the differential equation below. It would be nice if someone can help me out or guide how can I proceed. I have looked into many references, but I could not find something similar to the problem I have.
$$ ddddot{x} + frac{w_1}{w_2}ddot{x}+frac{1}{w_2}lambda(t) =0 $$

where, $$ lambda(t)= -c_1cdot t + c_2 $$ and $$w_1, w_2, c_1, c_2text{ are constants.}$$

Thanks in advance.
PS- I need to solve this analytically.

Create a symbolic link folder on a non-root Galaxy S7

I am trying to move my Whatsapp multimedia folder to my SD card because I have little space left on the internal memory.

Is there an option to do this without rooting the phone or installing shady apk?

How to use RiccatiSolve with a symbolic matrix

According to RiccatiSolve documentation of Eigensystem The method can be applied to symbolic matrices.
However, I can't get it to work, here is what I have tried so far:


RiccatiSolve[{{{1, 0}, {0, 1}}, m}, {{{1, 0}, {0, 1}}, {{1, 0}, {0, 1}}}, Method -> "Eigensystem"]

RiccatiSolve::matrix: Argument m at position {1, 2} is not a non-empty rectangular matrix.
RiccatiSolve[{{{1, 0}, {0, 1}}, {{1, 0}, {0, a}}}, {{{1, 0}, {0, 1}}, {{1, 0}, {0, 1}}}, Method -> "Eigensystem"]
RiccatiSolve::nonnum: RiccatiSolve has received a matrix with non-numerical elements.

Can someone tell me how to use a symbolic matrix with RiccatiSolve and what a symbolic matrix is.

Analytical solution of a symbolic set of equations

I have tried to solve a set of symbolic equations, but it continues to work and gives no results. The set of equations are:

a^2 + b^2 = A,
a c exp{(iota theta)} + bdexp{(iota phi)} = B,
c^2exp{(2iota theta)} + d^2exp{(2iota phi)} = C,
c^2 + d^2 = D

Since then, the number of variables exceeds the number of equations that I was hoping to find the (symbolic) solutions in terms of $ a $.

symbolic – Keep the equations in terms of specific variable

I am new to Mathematica and I am really struggling with something that seems simple. I'm trying to do an integration and keep the results in terms of a symbol $ T_1 $ and $ A_i $:

$$ T_1 = frac { text {pi} A_i} {2 J_a} $$

I want to integrate $ j_1 $:

$$ j_1 = J_a sin left ( frac { text {pi} t} {T_1} right) $$

The result I get is:

– frac {1} {2} A_i cos left ( frac {2 t J_a} {A_i} right) $$

I don't know how to get the results in terms of desired variables. I understand that Mathematica evaluates symbols as soon as possible, so I tried to play with Hold but that did not help. I also tried to recast the problem in the form of simultaneous equations and then use Solve or Eliminate as mentioned here:

Rewrite the expression in terms of factor

Here is an example of something I have tried:

$$ j_1 = J_a sin left ( frac { text {pi} t} { text {Hold} left (T_1 right)} right) $$

$$ a_1 = Integrate (%, t) $$

$$ text {ReleaseHold} left ( text {Solve} left ( left { text {expr} = a_1, T_j = T_1 right }, text {expr}, left {J_a right } right) right) $$

I tried to introduce $ T_j $ since i thought $ T_1 = T_1 $ probably wouldn't make sense.

The results are always in terms of $ J_a $ although:

$$ left { left { text {expr} to – frac { text {pi} A_i ^ 2 cos left ( frac {2 t J_a} {A_i} right)} {4 J_a T_j} right } right } $$

Any advice greatly appreciated!

pattern filtering – Find a minimal recoding of the (symbolic) entries of a $ 8 times 8 $ matrix

I have the following $ 8 times $ 8 matrix

{{1/3 (2 c(0,0)-c(1,0)-c(2,0)),(c(1,0)-c(2,0))/Sqrt(3),0,1/3 (-1+c(0,0)+c(0,1)+3 c(0,2)+c(1,0)+c(1,1)+c(2,0)+c(2,1)),-((-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3)),1/3 (2 c(0,1)-c(1,1)-c(2,1)),(c(1,1)-c(2,1))/Sqrt(3),0},{(c(1,0)-c(2,0))/Sqrt(3),1/3 (-2 c(0,0)+c(1,0)+c(2,0)),0,(-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3),1/3 (-1+c(0,0)+c(0,1)+3 c(0,2)+c(1,0)+c(1,1)+c(2,0)+c(2,1)),(c(1,1)-c(2,1))/Sqrt(3),1/3 (-2 c(0,1)+c(1,1)+c(2,1)),0},{0,0,-(1/3)+c(0,0)+c(1,0)+c(2,0),0,0,0,0,(-1+c(0,0)+2 c(0,1)+c(1,0)+2 c(1,1)+c(2,0)+2 c(2,1))/Sqrt(3)},{1/3 (2 c(0,1)-c(1,1)-c(2,1)),(c(1,1)-c(2,1))/Sqrt(3),0,1/3 (2 c(0,0)-c(1,0)-c(2,0)),(-c(1,0)+c(2,0))/Sqrt(3),1/3 (-1+c(0,0)+c(0,1)+3 c(0,2)+c(1,0)+c(1,1)+c(2,0)+c(2,1)),(-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3),0},{(-c(1,1)+c(2,1))/Sqrt(3),1/3 (2 c(0,1)-c(1,1)-c(2,1)),0,(-c(1,0)+c(2,0))/Sqrt(3),1/3 (-2 c(0,0)+c(1,0)+c(2,0)),-((-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3)),1/3 (-1+c(0,0)+c(0,1)+3 c(0,2)+c(1,0)+c(1,1)+c(2,0)+c(2,1)),0},{1/3 (-1+c(0,0)+c(0,1)+3 c(0,2)+c(1,0)+c(1,1)+c(2,0)+c(2,1)),(-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3),0,1/3 (2 c(0,1)-c(1,1)-c(2,1)),(-c(1,1)+c(2,1))/Sqrt(3),1/3 (2 c(0,0)-c(1,0)-c(2,0)),(c(1,0)-c(2,0))/Sqrt(3),0},{(-1+c(0,0)+c(0,1)+c(0,2)+c(1,0)+c(1,1)+2 c(1,2)+c(2,0)+c(2,1))/Sqrt(3),1/3 (1-c(0,0)-c(0,1)-3 c(0,2)-c(1,0)-c(1,1)-c(2,0)-c(2,1)),0,(c(1,1)-c(2,1))/Sqrt(3),1/3 (2 c(0,1)-c(1,1)-c(2,1)),(c(1,0)-c(2,0))/Sqrt(3),1/3 (-2 c(0,0)+c(1,0)+c(2,0)),0},{0,0,-((-1+c(0,0)+2 c(0,1)+c(1,0)+2 c(1,1)+c(2,0)+2 c(2,1))/Sqrt(3)),0,0,0,0,-(1/3)+c(0,0)+c(1,0)+c(2,0)}}

It has forty non-zero entries, some of which are duplicates and some of which are negatives of others. I want to map the entry (1,1) to t (1) and the following entries to t (i) or -t (i) – taking into account identities and "negative identities" – so that the length of the array of t is minimum.

In other words, what is the minimum number of t (i) I need to recode the original $ 8 times $ 8 matrix, and what mapping does it achieve?

My ultimate goal is to get the product and the sum of the singular values ​​of the matrix, and I hope that a succinct recoding of it could facilitate such a task.

Sleeping symbolic term and expression

Hello i have code whose terms look like g2''[y] E^[n I x] or n is 0,1,2, … I would like when n=0 for the E^[0 I x] conditions to stay E^[0 I x] and not be changed into one. For example, in symbolic calculations if I were to enter Mathematica

g2''[y] E^[0 I x]

he returns


where i would prefer him to come back

g2''[y] E^[0 I x].

Thank you.

simplify expressions – why does mathematics not return the result of the multiplication of a symbolic matrix and a symbolic vector?

I'm really stuck with this simple problem. This may not be entirely a problem. However, I do not understand why.

I am trying to multiply two things with a normal dot product.

Here is the code:

a = {{Ixx, 0, 0}, {0, Iyy, 0}, {0, 0, Izz}}
b = {{0}, {0}, {Theta1 & # 39;

a.b should work for the documentation of mathematics. And I await the result because,

{{0}, {0}, {Izz * Theta1 & # 39;
After // manipulating MatrixForm, it will be [0; 0; something].

But, after production a.b, I just take this:

enter description of image here

Thanks in advance.

Centos 8 symbolic link to the users' .ssh` folder

I follow this guide to configure some sort of ssh proxy for gitlab.

When I create a symbolic link like in this blog post, I cannot access the server by ssh. This is how the symbolic link is created.

lrwxrwxrwx. 1 git  git     28 Apr  4 19:39 /home/git/.ssh -> /opt/gitlab/gitlab/data/.ssh

here is the output of /opt/gitlab/gitlab/data/.ssh

-rw-------.  1 git  git  2768 Apr  4 19:03 authorized_keys
-rw-------.  1 git  git     0 Apr  4 19:03 authorized_keys.lock
-rw-------.  1 git  git   579 Apr  4 16:21 authorized_keys_proxy
-rw-------.  1 git  git  2610 Apr  4 16:21 id_rsa
-rw-r--r--.  1 git  git   179 Apr  4 19:57 known_hosts

and exit from /opt/gitlab/gitlab/data/

drwx------.  2 git            git    119 Apr  4 19:57 .ssh

When I copy all of these files from /opt/gitlab/gitlab/data/.ssh at /home/users/git/.ssh then ssh works fine. It seems that symbolic links are not being deleted correctly.

Please, is it possible to use symbolic links in the user .ssh directory and have ssh working?

I use centos 8 with activated selinux.

adb – Symbolic link from / sdcard to / sdcard

I am trying to get Google Markup to display its image elsewhere than in its default location. I have used different ROMs and versions of these ROMs, and every combination I have tried has a change of Google Markup output location. Google Markup doesn't seem to have any parameters to change its behavior, so I've tried to tailor its output to the desired location. The default output on my current configuration is at /storage/emulated/0/Android/media/, but I wish I had to /storage/emulated/0/Pictures/Screenshots/. I have tried the following from Windows ADB:

RMX1921:/ $ su
RMX1921:/ # ln -s /storage/emulated/0/Android/media/ /storage/emulated/0/Pictures/Screenshots/
ln: cannot create symbolic link from '/storage/emulated/0/Android/media/' to '/storage/emulated/0/Pictures/Screenshots//Markup': Operation not permitted
RMX1921:/ #

I'm using a Realme XT with DerpFest 10 build 2020-03-29 (Android 10r31) rooted with Magisk v20.4 if that's important. Is there a way to automatically redirect the output of Google Markup to another location?

Other things I would like to do:

  • The markup leaves the original file on this system (also one of the inconsistent behaviors of markup on different ROMs). I would like to get the filename of the original file and use it to rename the file generated by the markup. The format is: Screenshot_YYYYMMDD-hh-mm-ss.png.

  • After moving the file, delete the original file, which is located at /storage/emulated/0/Pictures/Screenshots/.

I'm thinking of a script that runs constantly in the background, doesn't have to be instant, maybe it triggers and checks and processes everything once every 5 seconds. But I feel like I could be too complicated. Ideas?

Thank you for your time.