## On this page

  

 

 # addVariable

 Last update: 16.07.2025 

abstract fun [addVariable](add-variable.md)(equation: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), displayName: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), isInput: [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html))

Add a variable.

#### Parameters

equationthe equationdisplayNamethe display nameisInputwhether the variable is an input#### Throws

[IllegalArgumentException](https://docs.oracle.com/javase/8/docs/api/java/lang/IllegalArgumentException.html)if the arguments are not valid[IllegalStateException](https://docs.oracle.com/javase/8/docs/api/java/lang/IllegalStateException.html)if a variable cannot be added right now