What is required as input for calculating a trend line using the trend function?

Calculating a trend line using the trend function requires historical actual values. This is essential because the trend function analyzes past data to identify patterns or trends within that data. The historical actual values provide the foundation upon which predictions or forecasts can be made. By examining these past data points, the trend function can establish the direction and slope of the trend line, which can then be projected into the future.

The other options do not serve as the primary basis for generating a trend line. Future predicted values and current live data do not provide the historical context needed for trend analysis. Additionally, comparative values from different worksheets could be useful for analysis but would not typically serve as direct input for calculating trend lines as they lack the historical consistency required for such calculations.