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## How do you replace a symbolic variable in MATLAB?

**subs( s )** returns a copy of s , replacing symbolic variables in s , with their values obtained from the calling function and the MATLAB^{®} Workspace, and then evaluates s . Variables with no assigned values remain as variables.

## How do I change a symbolic variable to numeric in MATLAB?

**Direct link to this answer**

- If you want to replace a symbolic variable with a numeric value in a symbolic expression, then use subs()
- You can always vpa() a symbolic expression to evaluate constant functions and convert most rational values into symbolic floating point values.

## How do you clear a symbolic variable in MATLAB?

To clear the assumption for the variable x , use the command assume(x,’clear’) . Alternatively, you can create a fresh symbolic variable without assumptions using syms . If you want to clear a symbolic variable and also reset the symbolic engine, **use the command clear all** .

## What are symbolic variables in MATLAB?

A symbolic variable **can hold an expression instead of just a numeric value**. For example it can hold the expression sin(x^2+1) . The symbolic toolbox can reason about the expressions, such as finding the solution to equations, or such as doing calculus. For example, syms x.

## How do you replace a variable in a matrix in MATLAB?

You can specify the value to replace as c , M(1,3) or M(3,1) . To replace a particular element of a matrix with a new value while keeping all other elements unchanged, use **the assignment operation**. For example, M(1,1) = 2 replaces only the first element of the matrix M with the value 2.

## What does double () do in MATLAB?

double( s ) **converts the symbolic value s to double precision**. Converting symbolic values to double precision is useful when a MATLAB^{®} function does not accept symbolic values. For differences between symbolic and double-precision numbers, see Choose Numeric or Symbolic Arithmetic.

## What does double mean in MATLAB?

double is **the default numeric data type (class)** in MATLAB^{®}, providing sufficient precision for most computational tasks. Numeric variables are automatically stored as 64-bit (8-byte) double-precision floating-point values. For example: x = 10; whos x. Name Size Bytes Class Attributes x 1×1 8 double.

## What is sym2poly in MATLAB?

c = sym2poly( p ) **returns the numeric vector of coefficients** c of the symbolic polynomial p . … sym2poly returns coefficients in order of descending powers of the polynomial variable.

## What is a symbolic variable?

A symbolic variable is **a string of characters that you define as a symbol**. Because the variable is a symbol, you can assign different values to it at different times. By assigning different values, you can do the same processing with different data.

## Why Syms is used in MATLAB?

The syms function **creates a variable dynamically**. For example, the command syms x creates the symbolic variable x and automatically assigns it to a MATLAB variable with the same name. The sym function refers to a symbolic variable, which you can then assign to a MATLAB variable with a different name.