abstract:In mathematics, the vertical line test is a test to determine if a curve is a relation or graph of a function when the function's domain and range correspond to the x and y axis of the Cartesian coordinate system. As a relation or graph of a function can only have one output for each unique input, such a Cartesian representation of the function can have at most a single y value for each x value.
The weekly OBV moved above its WMA on July 30, 2010 (see verticalline), and then as IWM dropped back to test the lows, the OBV was stronger (circle e) as it stayed above its WMA. At this time, the monthly OBV was positive from May 2009.