## 1. Symbolic substitution - MATLAB subs

Subs

This MATLAB function returns a copy of s, replacing all occurrences of old with new, and then evaluates s.

## 2. Evaluate Symbolic Expressions Using subs - MATLAB & Simulink

When you assign a value to a symbolic variable, expressions containing the variable are not automatically evaluated. Instead, evaluate expressions by using subs ...

Evaluate expressions and functions after their variables are assigned values.

## 3. subs (Symbolic Math Toolbox)

subs(S) replaces all occurrences of variables in the symbolic expression S with values obtained from the calling function, or the MATLAB workspace. subs(S ...

Symbolic substitution in a symbolic expression or matrix.

## 4. Substitute Variables in Symbolic Expressions - MATLAB & Simulink

Substitute variables with other variables, numbers, vectors, or matrices.

## 5. speed up "subs" function or faster alternative ways for symbolic ...

Jun 5, 2023 · I am simulating a robotic system with symbolic dynamic matrices of the robot. When I used "subs" function to substitute the symbolic ...

I am simulating a robotic system with symbolic dynamic matrices of the robot. When I used "subs" function to substitute the symbolic variables, it took around 0.03 seconds for 1 matrix. This is rel...

## 6. MATLAB: subs, eval - learnOnline

Variable substitution and expression evaluation: subs, eval. Suppose you have a symbolic expression f which includes the symbol x and you wish to substitute ...

Variable substitution and expression evaluation: subs, eval Suppose you have a symbolic expression f which includes the symbol x and you wish to substitute for x another symbol c or a numerical value x0. Then you can use the general subs command g=subs(f,old,new) which in our cases would be g=subs(f,x,c) or g=subs(f,x,x0). Here old, new can be arrays. The result g is still a symbolic variable or symbolic constant in “Maple”. Example 1: Consider a function of the two Cartesian coordinates f(x, y) = 2xy/(x2 + y2)2 . Change to polar coordinates using x = r cos θ, y = r sin θ and then determine the value of f at an arbitrary point on the unit circle r = 1. clear all syms x y r theta f=2*x*y/(x^2+y^2)^2; F=subs(f,[x y],[r*cos(theta) r*sin(theta)]); F=simple(F) % previous answer is messy f_on_unit_circle=subs(F,r,1) which gives the output F=sin(2*theta)/r^2 f_on_unit_circle=sin(2*theta) An alternative is to use the eval command. It is of the form ans=eval(S) where S is a symbolic expression for which at least one of its symbolic variables has just been given a value. If all variables are given numerical values, the answer is a number in MATLAB, not “Maple”. Example 2: Let us compare simple MATLAB and “Maple” codes which both evaluate the expression y = (x3 + 2) sec x at x = 0.123. MATLAB code Maple code using subs Maple code using eval clear all clear all clear all x=0.123 syms x syms x y=(x^3+2)*sec(x) S=(x^3+2)*sec(x); S=(x^3+2)*sec(x); y=subs(S,x,0.123) x=0.123; y...

## 7. Substitute Elements in Symbolic Matrices - MATLAB & Simulink

Use subs to substitute the element of B by specifying the variable name. For example, substitute B2_2 with 4. Get.

Substitute elements in symbolic matrices.

## 8. Symbolic substitution for multiple variables - MATLAB Answers

Dec 5, 2016 · Say my N is a 6x6 matrix with 5 symbolic variables and I want to evaluate N at one go, for 5 different values of the variables. How do I do that ...

Hi, I wanted some explanation on the captioned. Say my N is a 6x6 matrix with 5 symbolic variables and I want to evaluate N at one go, for 5 different values of the variables. How do I do that u...

## 9. problem with subs function - MATLAB Answers - MathWorks

Nov 30, 2016 · Error using sym/subs>normalize (line 206) The sizes of the second and third arguments are inconsistent. Error in ...

I use this command daily and sometimes it works and sometimes i get an error. I am obviously not understanding the complexity of such a simple function I have a simple symbolic function with ...