Creates a new trend line. Returns a Trendline object.

expression.Add(Type, Order, Period, Forward, Backward, Intercept, DisplayEquation, DisplayRSquared, Name)expressionRequired. An expression that returns one of the objects in the Applies To list.Type Optional . The type of trendline.

XlTrendlineType can be one of these XlTrendlineType constants.
xlExponential
xlLinear default
xlLogarithmic
xlMovingAvg
xlPolynomial
xlPower
Order Optional Variant. Required if Typeis xlPolynomial. The trendline order. Must be an integer from 2 through 6.Period Optional Variant. Required if Typeis xlMovingAvg. The trendline period. Must be an integer greater than 1 and less than the number of data points in the series you're adding a trendline to.Forward Optional Variant. The number of periods (or units on a scatter chart) that the trendline extends forward.Backward Optional Variant. The number of periods (or units on a scatter chart) that the trendline extends backward.Intercept Optional Variant. The trendline intercept. If this argument is omitted, the intercept is automatically set by the regression.DisplayEquation Optional Variant.Trueto display the equation of the trendline on the chart (in the same data label as the R-squared value). The default value is False.DisplayRSquared Optional Variant.Trueto display the R-squared value of the trendline on the chart (in the same data label as the equation). The default value is False.Name Optional Variant. The name of the trendline, as text. If this argument is omitted, Microsoft Graph generates a name.

Example

This example creates a new linear trendline on the chart.

myChart.SeriesCollection(1).Trendlines.Add