Move Coefficient to if/builtins

[zanete]

Sub of: #656

What

Why

Context

Prerequisites/resources

SoW (scope of work)

• documentation updated
• test cases added

Acceptance criteria

Given (Setup): Describes the initial state of the system or the preconditions for a change.

When (Action): Describes the specific action or behavior that is being tested/changed.

Then (Assertion): Defines the expected outcome or behavior of the system after the action in the "When" step is performed.

[zanete]

PR #646