Which graph is an example of a cubic function? On a coordinate plane, a parabola is shown. On a coordinate plane, a curve approaches x = negative 2 in quadrant 3, increases to a put of inflection at (0, 1), and then increases again and approaches x = 2. On a coordinate plane, a straight line has a positive slope. On a coordinate plane, a function has a line with positive slope that intersects with a line with a negative slope.