How to create custom functions in Rack
Navigate to the Settings page
Click "Custom Functions"
Click the blue "Add New" new button
Enter a name for the custom function
Enter the mathematical expression for the function based on the rule listed to the right side of the page
Click the icon that is two arrows arranged in a circle located to the right of the equation
Map the exercises to the correct place within the equation using the "Select Exercise" drop downs
Click the white floppy disc icon to save