# Equations and Formulae

Many primitives allow you to enter equations that determine their values or behavior. To access the equation editor for a primitive, hover your mouse over the primitive and click the "=" sign that appears. You can also use the configuration panel on the right side of the main window to edit the equation when the primitive is selected.

The equation editor allows you to type in an equation. On the bottom of the editor are a list of functions built into Insight Maker. If you hover over a function, a tooltip will describe what it does. On the right side of the editor are a list of other primitives this primitive can reference. You can click on one of these to insert it into the equation.

These equations can be arbitrary mathematical or programming expressions. For instance, take the example of the following equation:

Sin(Years()*2) + **[Rain Flow]**^0.05

This example displays a number of features that the Insight Maker equation engine supports:

- ‘Years’ refers to the current simulation time as measured in years.
- ‘[Rain Flow]’ refers to the value of another primitive. Primitives can reference each other using this square-bracket notation.
- ‘Sin’ applies the trigonometric sine function.
- ‘+’, ‘*’, and ‘^’ are all standard mathematical operators representing addition, multiplication and exponentiation respectively.

There are a wide range of built-in functions you can use to develop equations and many advanced programming features that can also be utilized.