# simscapeEquation

Convert symbolic expressions to Simscape language equations

## Syntax

``simscapeEquation(f)``
``simscapeEquation(LHS,RHS)``

## Description

example

````simscapeEquation(f)` converts the symbolic expression `f` to a Simscape™ language equation. This function call converts any derivative with respect to the variable `t` to the Simscape notation `X.der`. Here `X` is the time-dependent variable. In the resulting Simscape equation, the variable `time` replaces all instances of the variable `t` except for derivatives with respect to `t`.`simscapeEquation` converts expressions with the second and higher-order derivatives to a system of first-order equations, introducing new variables, such as `x1`, `x2`, and so on.```

example

``simscapeEquation(LHS,RHS)` returns a Simscape equation `LHS == RHS`.`

## Examples

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Convert the following expressions to Simscape language equations.

```syms t x(t) y(t) phi = diff(x) + 5*y + sin(t); simscapeEquation(phi) simscapeEquation(diff(y),phi)```
```ans = 'phi == sin(time)+y*5.0+x.der;' ans = 'y.der == sin(time)+y*5.0+x.der;'```

Convert this expression containing the second derivative.

```syms x(t) eqn1 = diff(x,2) - diff(x) + sin(t); simscapeEquation(eqn1)```
```ans = 'x.der == x1; eqn1 == sin(time)-x1+x1.der;'```

Convert this expression containing the fourth and second derivatives.

```eqn2 = diff(x,4) + diff(x,2) - diff(x) + sin(t); simscapeEquation(eqn2)```
```ans = 'x.der == x1; x1.der == x2; x2.der == x3; eqn2 == sin(time)-x1+x2+x3.der;'```

## Tips

• The equation section of a Simscape component file supports a limited number of functions. For details and the list of supported functions, see Simscape `equations` (Simscape). If a symbolic equation contains functions that are not available in the equation section of a Simscape component file, `simscapeEquation` cannot convert these equations correctly to Simscape equations. Such expressions do not trigger an error message. Expressions with infinities are prone to invalid conversion.

## Version History

Introduced in R2010a