So, I have just to begin studying Calculus, but I have questions about the tangent and secant lines. From my interpretation, it seems that the tangent line is used to find the rate of change at one particular point on the graph, while using using secant lines to find the approxiamate rate of change as it nears that particular point; and the secant lines are purposed to find the average rate of change between two points that are, consequently, connected by the secant line. Is this false, or are two somewhat true uses these lines?