Answered
How to calculate the equation with letter and variable
Use <https://www.mathworks.com/help/symbolic/subs.html?s_cid=ans2doc_man_link subs> to substitute values, as shown below. You on...

7 years ago | 2

Answered
Solving a System of 2nd Order Linear ODE? "Explicit solutions cannot be found"
Since you're starting with floating point numbers, you should try a numerical simulation using ode45 or other numeric ODE solver...

7 years ago | 0

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How can I find ranges of inequalities using solve in live script
Try the 'ReturnConditions' option: syms x ineq = x^4 +7*x -3*x^3 -6 > 0; S = solve(x^4 +7*x -3*x^3 -6 > 0, x,'IgnoreA...

7 years ago | 1

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Answered
How can I extract an expression for a variable from an equation?
Can you post your code? And, try using the "solve" function. To declare the equation, use "==". sym x y z eqn = sin(z...

7 years ago | 1

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Create an symbol array
Starting R2010b >> A = sym('A',[2 3]) A = [ A1_1, A1_2, A1_3] [ A2_1, A2_2, A2_3] >> A = sym('A%d%d',[2 3]) ...

7 years ago | 0

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Substition of variables in a matrix
This works. Example is below. Can you provide the code for getting Adiff? Are you creating Xi,Yi,Zi first and using them to crea...

7 years ago | 0

Answered
How to plot inequality?
Here's an example of plotting an inequality. You'll need to adapt it. >> v = -5:0.1:5; [x,y] = meshgrid(v); % create a ...

7 years ago | 1

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create symbolic expressions when using ndgrid
If I understand correctly, you are trying to do something like this? >> A = sym('A%d',[1 4]); B = sym('B%d',[1 4]); >...

7 years ago | 0

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Symbolic variable from a Script/Workspace to Simulink function for calculations
By "only numeric matrix", I assume that your Block Parameter only accepts numbers? If so, can you convert the symbolic matrix to...

7 years ago | 0

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String to Sym deprecated
As the warning says, please don't use string input. Is this helpful? syms a b = sym(a+1) If you store strings, then u...

7 years ago | 0

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System of parametric equations, symbolic solution
The MATLAB "solve" ignores special cases. Here, it ignores the case "b = c" and thus cannot find a solution. Since it cannot fin...

7 years ago | 0

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Precise conversions from double to symbolic
Use quotes to keep your input exactly as it. r = sym('1.78503') But you don't get the fractional representation since yo...

7 years ago | 0

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Problem with "Conversion to logical from sym is not possible."
Since you MATLAB isn't new enough to have piecewise, you can use heaviside as a substitute for piecewise. FDInt = 1/(0.27+e...

7 years ago | 0

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How to install symbolic toolbox if I have a student version of matlab
If this command works, you already have it. syms x If it errors, then add it from Addons: <https://www.mathworks.com/hel...

7 years ago | 2

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Integrate a piecewise function (Second fundamental theorem of calculus)
This is the same question as <http://www.mathworks.com/matlabcentral/newsreader/view_thread/347103?s_cid=ans2doc_man_link http:/...

7 years ago | 3

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replace expression of variables with an equivalent variable?
Your substitution can't work because you defined "theta_v" to be "omega*t + phi_v". So you're just substituting "omega*t + phi_v...

7 years ago | 1

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Answered
Trigonometric Power Reduction Formulas using Symbolic Matlab
Here, you want to change the input from "sin" from "a" to cos with "2*a". Essentially, you want make the argument of the functio...

7 years ago | 4

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Answered
symbolic of cos with power
Here, you want to change the input of "cos" from "x" to "2*x". Essentially, you want make the argument of "cos" more complicated...

7 years ago | 0

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Numerical values of integrals
Use "vpaintegral" introduced in 16b: <https://www.mathworks.com/help/symbolic/vpaintegral.html?s_cid=ans2doc_man_link https://ww...

7 years ago | 2

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Getting Both Symbolic Output and Numeric Output
Calculate the answer symbolically and substitute values in at the end. Start with symbolic matrices and variables ... sy...

7 years ago | 0

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Answered
syms a b c x is not working with MuPAD
The "syms" command is for MATLAB and not for MuPAD.

7 years ago | 0

Answered
How do I place a two-lined title, x-label, y-label, or z-label on my plot?
Replace spaces with "\newline". labels = {'line1 line2','line1 line2','line1 line2'}; labels = cellfun(@(x) strrep(x,' '...

7 years ago | 22

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vpasolve not returning an answer, just Empty sym: 0-by-1
Your equation is never satisfied. Hence, "vpasolve" returns empty sym. Here's how to figure that out. First, declare your equ...

7 years ago | 2

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Answered
How do you create a symbolic function that takes a vector input?
You almost got it right! In fact, you just need to _delete_ a line of code. Don't declare "a" as a 1x3 vector because "a" can be...

7 years ago | 0

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Answered
Strange ilaplace answer?????
Use "vpa" to solve for the roots and get a result in terms of "t" as documented here: <http://www.mathworks.com/help/symbolic/ro...

7 years ago | 7

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How can I plot the region for two inequalities?
Here's how to numerically evaluate the conditions and visualize them. v = -5:0.01:5; % plotting range from -5 to 5 [x y]...

7 years ago | 7

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Answered
How can I use a ifft function to a symbolic variable ?
I'm assuming your error said: Undefined function 'ifft' for input arguments of type 'sym'. As the error message says, t...

8 years ago | 0

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Remove or ignore a particular row while reading from text files?
Could you find all elements of Cstr with '[7E8]' and delete them? Cstr = textread(file2{i2}, '%s', 'delimiter', ''); idx...

8 years ago | 0

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MuPAD Fails to Solve a Simple Inequality
solve's answer is correct. You can verify it as: syms X ndot4B xiA ndot4A xiB eqn = X*ndot4B*xiA - ndot4B*xiA + X*ndot4A...

8 years ago | 0

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Jacobi polynomials in MATLAB
Your first argument "j-3" is negative for j=0,1,2. That's what the error message says: A nonnegative integer or a symbol is expe...

8 years ago | 0