Unit 1.4.7, of BUS101:Introduction to business, says "Business cycles are usually measured by considering the **growth rate** of real gross domestic product."

It also defines an expansion as the time when GDP rises and a contraction as the time when GDP declines.

At the end of the lesson is the following graph:

For some reason, they give a graph of GNP rather than GDP but following the definitions, since the y axis is showing the “growth rate,” does this mean that the first point where the line crosses the x axis is a trough because the rate goes from negative (that is decreasing GDP/GNP) to positive (i.e. increasing GDP/GNP)?